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PubMed2006

Use of benzodiazepines and benzodiazepine-related drugs among 223 patients with an acute hip fracture in Finland: Comparison of benzodiazepine findings in medical records and laboratory assays.

BACKGROUND AND OBJECTIVE: CNS drugs are a risk factor for falls and fractures among older people. Our aim was to describe the use of benzodiazepines and benzodiazepine-related drugs among patients admitted to two Finnish hospitals as a result of an acute hip fracture, and to analyse the concordance of benzodiazepine findings from different data sources. PATIENTS AND METHODS: We studied the use of benzodiazepines and benzodiazepine-related drugs by (i) asking the patient or his/her relatives about his/her use of hypnotics; (ii) checking the patient's medical records; and (iii) analysing for the presence of benzodiazepines in serum and urine. Blood and urine samples were taken at admission. Detection of benzodiazepines in serum and urine was achieved by the fluorescence polarisation method. Concordance in benzodiazepine findings between medical records and laboratory results was estimated by calculating the degree of agreement (kappa) and described graphically using a Venn diagram. RESULTS: A total of 223 patients were enrolled in the study. Of these, 71% were women. The mean age of women was 80.5 years (SD: 10) and of men, 73 years (SD: 12) [p < 0.0001]. Thirty percent of the patients reported that they used hypnotics. Benzodiazepine in serum or urine was detected in 83 (37%) patients. Over half of the patients coming from residential homes (53%) and institutions (54%) were benzodiazepine-positive. For home dwellers the proportion of patients that were benzodiazepine-positive was 29%. In 48% (40/83) of the benzodiazepine-positive patients, the type of benzodiazepine could not be identified because of a lack of drug records regarding benzodiazepines. A total of 113 (51%) patients used benzodiazepines or benzodiazepine-related drugs when both laboratory results and medical drug records were taken into account. Thirty-nine percent of these patients were home dwellers, 69% came from residential care and 76% from institutional care. The concordance between medical records and laboratory results expressed as overlap area was 32% in men and 59% in women, 38% in community-dwelling patients, 63% in residential home patients, and 68% in patients from institutions. CONCLUSION: Half of patients with an acute hip fracture used benzodiazepines or benzodiazepine-related drugs. The highest prevalences were found in institutional and residential care where it should be well known that the use of CNS drugs increases the risk of hip fracture. Concordance of benzodiazepine findings was moderate in all patients and poorest among men. Concordance was poorer among home dwellers than among those living in residential homes and institutions. Analysing benzodiazepine in serum seems to be the most reliable method for ascertaining benzodiazepine exposure. This laboratory test could be performed routinely when the elderly patient is admitted to hospital because of a fall or, at least, in case of hip fracture. Then, if needed, the patient should be informed about the risks of benzodiazepine use, and further falls and fractures could be prevented.

Accidental Falls↗

PubMed2000

Antidepressant plus benzodiazepine for major depression.

BACKGROUND: Anxiety frequently coexists with depression. There is no systematic review to show if adding benzodiazepines to antidepressants can bring about any advantage over antidepressants alone in the treatment of depression, although such a combination prescription appears to be widely practiced worldwide OBJECTIVES: To determine whether, among adult patients with major depression, adding benzodiazepines to antidepressants brings about any benefit in terms of symptomatic recovery or side-effects in the short term (less than 8 weeks) and long term (more than 2 months), in comparison with treatment by antidepressants alone. SEARCH STRATEGY: Electronic searches of MEDLINE, EMBASE, International Pharmaceutical Abstracts, Biological Abstracts, LILACS, PsycLit, the Cochrane Library and the trial register of the Cochrane Depression, Anxiety and Neurosis Group (January 1972 to December 1998), combined with hand searching, reference searching, SciSearch and personal contacts. SELECTION CRITERIA: All randomized controlled trials that compared combined antidepressant-benzodiazepine treatment with antidepressant alone for adult patients with major depression (Feighner criteria, RDC, DSM-III, DSM-III-R, DSM-IV or ICD-10). Exclusion criteria are: antidepressant dosage lower than 100 mg of imipramine or its equivalent daily and duration of trial shorter than 4 weeks. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed the eligibility and quality of the studies. Two reviewers independently extracted the data. Standardized weighted mean differences and relative risks were estimated with random effects model. The dropouts were assigned the least favorable outcome. Two sensitivity analyses examined the effect of this assumption as well as the effect of including medium quality studies. Three a priori subgroup analyses were performed with regard to the patients with or without comorbid anxiety and with regard to the types of benzodiazepines tested. MAIN RESULTS: Aggregating nine studies with a total of 679 patients, the combination therapy group was 37% (95%CI: 19 to 51%) less likely to drop out than the antidepressant alone group. The intention-to-treat analysis showed that the former were 63% (18 to 127%) to 38% (15 to 66%) more likely to show response (defined as 50% or greater reduction in the depression scale from baseline) up to 4 weeks. REVIEWER'S CONCLUSIONS: The potential benefits of adding a benzodiazepine to an antidepressant must be balanced judiciously against possible harms including development of dependence and accident proneness, on the one hand, and against continued suffering following no response and drop-out, on the other.

Adult↗

PubMed1984

Molecular aspects of the action of benzodiazepine and non-benzodiazepine anxiolytics: a hypothetical allosteric model of the benzodiazepine receptor complex.

The availability of radiolabeled benzodiazepines has resulted in the identification of high affinity receptors in the central nervous system for this class of psychotherapeutic agent which are linked to recognition sites for the inhibitory neurotransmitter, GABA. Evaluation of new, synthetic compounds in the benzodiazepine radioligand binding assay has resulted in the identification of nine classes of non-benzodiazepine putative anxiolytic agents, some of which may be more anxioselective than the benzodiazepines. At least three and possibly five subclasses of benzodiazepine receptor have been identified in mammalian tissues using radioligand binding assays. The possibility exists that one of these receptor subclasses may mediate the anxiolytic effects of the benzodiazepines while the remainder may be involved in the mediation of the sedative, ataxic and anticonvulsant properties associated with benzodiazepine-like agents. Several endogenous ligands for the benzodiazepine receptor(s) have been postulated. These include various proteins and peptides, purines and the beta-carbolines. This latter group, which competitively antagonizes the pharmacological and biochemical effects of the benzodiazepines, has the highest affinity for the benzodiazepine receptor of all compounds thus far examined; however, none of these compounds has been conclusively identified as the endogenous ligand akin to the enkephalins and endorphins at the opiate receptor. The majority of available evidence would indicate that the endogenous ligand for the benzodiazepine receptor(s) is an antagonist of the benzodiazepines and other putative anxiolytic agents.

Animals↗

PubMed1987

Synthesis of beta-carboline-benzodiazepine hybrid molecules: use of the known structural requirements for benzodiazepine and beta-carboline binding in designing a novel, high-affinity ligand for the benzodiazepine receptor.

Hybrid molecules incorporating pharmacologically important structural features of both 3-carboxy-beta-carbolines and 1,4-benzodiazepines were synthesized, and their affinities for the benzodiazepine receptor were determined in vitro. One of these hybrids, 8,14-dioxo-13,14-dihydro-8H-indolo[3',2':4,5]pyrido[2,1-c] [1,4]benzodiazepine (13), demonstrated high affinity for the receptor, displacing both benzodiazepines (IC50 = 23 nM) and beta-carbolines (IC50 = 47 nM) from their binding sites. Of the compounds synthesized, 13 also most closely satisfied the structural requirements that generally ensure a high affinity of both beta-carbolines and benzodiazepines for the receptor (e.g., aromaticity of the beta-carboline, presence of a carbonyl at C-3 of the beta-carboline and of a pi 2-region on the benzodiazepine). The hybrids not fulfilling these requirements had no affinity for the receptor. In vivo pharmacological properties of 13 could not be demonstrated because of its metabolic instability and/or its poor transport into the brain. The results are discussed in terms of a possible overlapping of beta-carboline binding sites with those of benzodiazepines on the receptor.

Animals↗

PubMed1982

A three-state model of the benzodiazepine receptor explains the interactions between the benzodiazepine antagonist Ro 15-1788, benzodiazepine tranquilizers, beta-carbolines, and phenobarbitone.

The potent benzodiazepine receptor ligands beta-carboline-3-carboxylic acid ethyl ester (beta-CCE) and the corresponding methylester (beta-CCM) administered i.v. depressed segmental dorsal root potentials in spinal cats, reversed the prolongation of dorsal root potentials by phenobarbitone, and abolished the depression of a motor performance task induced by phenobarbitone in mice; beta-CCE enhanced the low-frequency facilitation of pyramidal population spikes in the hippocampus of anaesthetized rats. These effects of beta-carbolines reflect a depression of GABAergic synaptic transmission and, thus, are diametrically opposed to the enhancing action of benzodiazepine tranquilizers. The specific benzodiazepine antagonist, Ro 15-1788, while not affecting dorsal root potentials, hippocampal population spikes or phenobarbitone-induced motor performance depression, abolished the effects of beta-CCE on the three parameters and similar effects of beta-CCM on the spinal cord and motor performance. A three-state model of the benzodiazepine receptor is proposed in which benzodiazepine tranquilizers act as agonists enhancing the function of the benzodiazepine receptor as a coupling unit between GABA receptor and chloride channel, beta-carbolines act as "inverse agonists" reducing this coupling function, and Ro 15-1788 represents a competitive antagonist blocking both the enhancing effect of agonists and the depressant effect of "inverse agonists" on GABAergic synaptic transmission.

Animals↗

PubMed1983

[1,5-benzodiazepines. V. Synthesis of pyrazolo (3,4-b)(1,5)benzodiazepines and 5H-pyrimido(4,5-b)(1,5)benzodiazepines].

The reaction of 4-(dialkylamino)-1,3-dihydro-2H-1,5-benzodiazepin-2-ones (I a-c) with N,N-dimethylformamide in the presence of phosphorus pentachloride at room temperature gave rise to the formation of 4-(dialkylamino)-3-[(dimethylamino)methylene]-1,3-dihydro-2H-1,5-benzodiazepin- 2-ones (IX a-c) which were useful starting materials to achieve the synthesis of tricyclic 1,5-benzodiazepine derivatives. Actually (IX a), selected for the smallest steric hindrance of the 4-dialkylamino substituent, by reaction with hydrazines afforded pyrazolo[3,4-b][1,5]benzodiazepine derivatives whereas reaction with guanidine or amidines gave 5H-pyrimido-[4,5-b][1,5]benzodiazepine derivatives. The structure of isomeric N-methyl-pyrazoles (X c) and (XI a) and of N-phenylpyrazole (X b) were elucidated by comparison with compounds prepared by unequivocal chemical methods. Pharmacological evaluation of some of the products showed only generic CNS depressant activity.

Animals↗

PubMed2002

1,5-benzodiazepines. Part XIII. Substituted 4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepin-5-amines and 4H-imidazo[1,2-a][1,5]benzodiazepin-5-amines as analgesic, anti-inflammatory and/or antipyretic agents with low acute toxicity.

The reaction of proper N,N-dialkyl-4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepin-5-amines (1) with N-chlorosuccinimide afforded their 4-chloroderivatives 3 which in turn were treated with cyclic amines to give the corresponding 4,5-diaminoderivatives 4. The N,N-dialkyl-4H-imidazo[1,2-a][1,5]benzodiazepin-5-amines (5) were prepared starting from suitable 4-(dialkylamino)-1,3-dihydro-2H-1,5-benzodiazepin-2-ones (8), through multistep synthetic routes. At the 200 mg kg(-1) os dose, some compounds 3 and 4 showed notable analgesic or anti-inflammatory activity but no antipyretic properties, whereas the 5-(dibutylamino) derivatives 5b and 5f proved to be significantly endowed with all these activities. Almost all the compounds 3, 4 and 5 did not show acute toxicity in mice up to 800 mg kg(-1) os dose.

Analgesics↗

PubMed1977

Double-blind cross-over clinical comparison of two 2'-chloro benzodiazepines: 7-chloro-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one (chlordesmethyldiazepam) versus 7-chloro-5-(o-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one (lorazepam) in neurotic anxiety.

A group of 20 female neurotic inpatients has been treated with 7-chloro-5-(2-chlorophenyl)-1,3-dihydro-2H-1,4-benzodiazepin-2-one-(chlordesmethyldiazepan)- 7-chloro-5(o-chlorophenyl)-1,3-dihydro-3-hydroxy-2H-1,4-benzodiazepin-2-one (lorazepam) according to a double-blind cross-over design. For each drug clinical evaluations were performed by means of Hamilton's rating scale for anxiety states and of Overall and Gorham's brief psychiatric rating scale, at the beginning, after the first week and at the end of the two-week period of treatment, in opposite sequence. A statistically greater efficacy of chlordesmethyldiazepam in comparison to lorazepam was observed. Results are discussed with regard to benzodiazepine structure-activity relationships.

Adult↗

PubMed1982

(+/-)-4-Aryl-4,5-dihydro-3H-1,3-benzodiazepines. 2. Nuclear-substituted analogues of (+/-)-4,5-dihydro-2,3-dimethyl-4-phenyl-3H-1,3-benzodiazepine and (+/-)-4,5-dihydro-2-ethyl-3-methyl-4-phenyl-3H-1,3-benzodiazepine as potential antidepressant agents.

Antidepressant-like activity, as evidenced by marked inhibition of tetrabenazine-induced ptosis, was previously reported for (+/-)-4,5-dihydro-4-phenyl-3H-1,3-benzodiazepine derivatives. Since optimal antitetrabenazine activity was associated with (+/-)-4,5-dihydro-2,3-dimethyl-4-phenyl-3H-1,3-benzodiazepine (9k, HRP 543) and the 2-ethyl-3-methyl analogue (10k), the synthesis and evaluation of nuclear-substituted derivatives of these two compounds was also investigated. The initial synthesis involved Friedel-Crafts acylation of substituted benzenes with 2-nitrophenylacetyl chloride to afford 1-aryl-2-(2-nitrophenyl)ethanones 2, which were converted in five steps to (+/-)-alpha-aryl-N-methyl-2-nitrobenzeneethanamines 7. Greater flexibility with respect to the introduction of nuclear substituents was achieved by conversion of 2-nitrotoluene derivatives to 2 via acylation of intermediate beta-(dimethylamino)-2-nitrostyrenes with various aroyl chlorides and hydrolysis. Reductive amination of 2 with methylamine and sodium cyanoborohydride afforded 7 directly and significantly reduced the number of synthetic steps. Reduction of 7a-j to diamines 8a-j and cyclization with appropriate ortho esters gave nuclear-substituted analogues of 9k and 10k. Marked antitetrabenazine activity was associated with many of these compounds. Significant enhancement of activity with respect to the unsubstituted analogues 9k and 10k was not observed, with the exception of 9c which appeared to be slightly more potent than 9k.

Amphetamine↗

PubMed1992

1,5-Benzodiazepines. X. Dialkylamino substituted 1,5-benzodiazepine and [1,2,4]triazolo [4,3-a][1,5] benzodiazepine derivatives with inhibitory activity on PAF-induced platelet aggregation.

Novel 4-(dialkylamino) substituted (4, 5 c, 8) and 2,4-bis(dialkylamino) substituted (6) 1,5-benzodiazepine derivatives were synthesized. Both these new compounds and the substituted 4H-[1,2,4]triazolo[4,3-a][1,5]benzodiazepine-5-amines 2 a-h, recently described by us, were tested in vitro for their inhibitory activity on the PAF-induced aggregation of human platelets. Actually, bicyclic compounds 4 d, 5 c and tricyclic compounds 2 g, h showed a significant activity: in all them the dialkylamino substituent was the 4-(ethoxycarbonyl)-1-piperazinyl group. On the contrary, compounds 4 d, 5 c, 2 g,h showed practically no inhibitory activity when platelet aggregation was induced by ADP, A23187, or collagen.

Benzodiazepines↗

PubMed1988

Tetrazepam: a benzodiazepine which dissociates sedation from other benzodiazepine activities. II. In vitro and in vivo interactions with benzodiazepine binding sites.

Tetrazepam is a 1,4-benzodiazepine (BZD) derivative which, in rodents, appears to have very little sedative and ataxic effects. In an attempt to identify the molecular mechanisms underlying this particular pharmacological profile we examined the interaction of tetrazepam with BZD binding sites. Tetrazepam interacted competitively with "central" and "peripheral" BZD binding sites and exhibited comparable affinities for both sites. Tetrazepam was approximately one-seventh as potent as diazepam at the central receptor and as potent as diazepam at the peripheral binding site. Tetrazepam did not distinguish type I from type II central BZD receptors, as evidenced by comparable affinities for the cerebellar and hippocampal receptors. In vitro autoradiographic studies showed that tetrazepam displaced [3H]flunitrazepam from rat brain membranes without any clear regional specificity. Like all BZD receptor agonists, tetrazepam exhibited a gamma-aminobutyric acid shift, a photoaffinity shift and potentiated the binding of 35S-t-butyl-bicyclophosphorothionate to rat brain membranes. However, the latter effect was observed at relatively high concentrations of tetrazepam. In vivo, tetrazepam displaced specifically bound [3H]flunitrazepam from mouse brain (ID50, 37 mg/kg p.o. vs 3.5 mg/kg p.o. for diazepam) and from mouse kidney (ID50, 38 mg/kg p.o. vs. 21 mg/kg p.o. for diazepam). It is concluded that tetrazepam is a BZD receptor agonist; the molecular mechanisms which underly the low sedative potential of the drug cannot at present be explained by a particular interaction with either central or peripheral BZD binding sites, but may be related to the drug's relatively weak effect on 35S-t-butyl-bicyclophosphorothionate binding.

Animals↗

PubMed1987

The role of benzodiazepine receptors in the induction of differentiation of HL-60 leukemia cells by benzodiazepines and purines.

A series of benzodiazepines was evaluated for their capacity to induce the differentiation of HL-60 acute promyelocytic leukemia cells. Benzodiazepines were effective initiators of maturation in the concentration range of 50 to 150 microM. The possible involvement of benzodiazepine receptors in mediating the differentiation induced by these agents was investigated. The presence of high affinity, peripheral type benzodiazepine binding sites (KD = 7.3 nM, TB = 14.5 pmol/mg protein with Ro5-4864) was demonstrated in HL-60 membranes. The occupancy of peripheral type high affinity benzodiazepine receptors by various benzodiazepines showed some correlation (r = 0.76) with their differentiation-inducing capabilities, but binding potencies were 1,000-fold higher than the concentrations required to produce differentiation. A class of benzodiazepine receptors with lower binding affinity was also detected in HL-60 membranes (KD = 28.6 microM; TB = 199 pmol/mg protein with diazepam). A higher level of correlation (r = 0.88) was demonstrated between benzodiazepine occupancy of these lower affinity receptors and the capacity to induce maturation. Significantly, benzodiazepine concentrations needed for low affinity binding and induction of differentiation were the same (25-200 microM), suggesting that low affinity benzodiazepine receptors may be involved in the induction process. We have shown that the molecular form responsible for the induction of the differentiation of HL-60 cells to mature forms by 6-thioguanine (TGua) is the free base, TGua, itself [Ishiguro, Schwartz, and Sartorelli (1984) J. Cell. Physiol., 121:383-390]. Since hypoxanthine (Hyp) and inosine (Ino) have been identified as putative endogenous ligands for high affinity benzodiazepine receptors in brain tissue, the potential involvement of benzodiazepine receptors in the differentiation of HL-60 cells by the purines was investigated. Physiological purines such as Hyp and Ino were inactive in displacing the benzodiazepines from their high and low affinity binding sites in HL-60 membranes. In contrast, TGua caused inhibition of benzodiazepine binding to high and low affinity sites. The inhibition of Ro5-4864 binding to high affinity binding sites by TGua appeared to be due to the binding of TGua to membranes through the formation of a mixed disulfide between the 6-thiopurine and protein thiols, since the inhibition was reversed by the presence of 2-mercaptoethanol. The findings suggest a possible relationship between the occupancy of benzodiazepine receptors by TGua and the induction of leukemic cell differentiation.

Benzodiazepines↗

PubMed1986

Demonstration and purification of an endogenous benzodiazepine from the mammalian brain with a monoclonal antibody to benzodiazepines.

Four hybridoma lines secreting monoclonal antibodies to benzodiazepines were produced after BALB/c mice were immunized with a benzodiazepine-bovine serum albumin conjugate. The monoclonal antibodies were purified from ascites fluids, and their binding affinities for benzodiazepines and other benzodiazepine receptor ligands were determined. These antibodies have very high binding affinities for diazepam, flunitrazepam, Ro5-4864, Ro5-3453, Ro11-6896, and Ro5-3438 (the Kd values are in the 10(-9) M range). However, these antibodies have very low affinities for the benzodiazepine receptor inverse agonists (beta-carbolines) and antagonists (Ro15-1788 and CGS-8216). One of the monoclonal antibodies (21-7F9) has been used to demonstrate the existence of benzodiazepine-like molecules in the brain and for the purification of these molecules. Immunocytochemical experiments show that these molecules are neuronal and not glial and that they are ubiquitously distributed throughout the brain. Immunoblots indicate the presence of benzodiazepine-like epitopes in several brain peptides. An endogenous substance that binds to the central-type benzodiazepine receptor with agonist properties has been purified to homogeneity from the bovine brain. The purification consisted on immunoaffinity chromatography on immobilized monoclonal anti-benzodiazepine antibody followed by gel filtration on Sephadex G-25 and two reverse phase HPLCs. The purified substance has a small molecular weight and its activity is protease resistant. The endogenous substance blocks the binding of agonists, inverse agonists and antagonists to the central-type benzodiazepine receptor but it does not inhibit the binding of Ro5-4864 to the peripheral-type benzodiazepine receptor. The neurotransmitter gamma-aminobutyric acid increases the affinity of the benzodiazepine receptor for the purified substance. Preliminary evidence indicates that the purified substance is a benzodiazepine with a molecular structure that is identical or very close to N-desmethyldiazepam.

Animals↗

PubMed1999

Long-term benzodiazepine users--characteristics, views and effectiveness of benzodiazepine reduction information leaflet.

OBJECTIVE: The authors looked at the clinical characteristics of long-term benzodiazepine users and how they viewed their use of benzodiazepine. We also examined the effectiveness of a self-help leaflet on reducing benzodiazepine use. METHOD: One hundred and nine long-term benzodiazepine users (daily use for more than 1 year) were assessed. Their perceived beneficial and undesirable effects of benzodiazepine and intention to reduce benzodiazepine use were studied and their history of benzodiazepine use was obtained. Psychiatric diagnosis and medical history were reviewed. A self-help leaflet was provided to 56 users whose anxiety symptoms were assessed to have been under control. We re-examined these 56 users 3 months later on their use of benzodiazepine and anxiety levels. RESULTS: The 109 long-term benzodiazepine users used a therapeutic dose of benzodiazepine (median: 10 mg diazepam equivalent) regularly for a median of 9 years (range: 1-40). Most of the users found benzodiazepine helpful and only 11% of them reported undesirable side effects. Half of the 109 subjects refused to reduce the dosage. Most of the subjects still experienced significant anxiety despite the use of benzodiazepine. Fourteen of the 56 subjects provided with a self-help leaflet were able to reduce a median of 2.5 mg of diazepam equivalent when re-examined after 3 months. CONCLUSION: The results are compared with previous studies in Western societies and are discussed in the light of clinical management of patients with anxiety disorders.

Anti-Anxiety Agents↗

PubMed1996

Azirino[1, 2-d][1, 4]benzodiazepine derivatives and related 1,4-benzodiazepines as anticonvulsant agents in DBA/2 mice.

1. The behavioral and anticonvulsant effects of several 1, 4-benzodiazepine (BDZ) and azirino[1,2-d] [1, 4]benzodiazepine (ABDZ) derivatives were studied after intraperitoneal administration in DBA/2 mice, a strain genetically susceptible to sound-induced seizures. 2. The anticonvulsant effects were evaluated on seizures evoked by means of auditory stimulation (109 dB, 12-16 kHz) in animals placed singly under a Perspex dome. 3. The 1,4-benzodiazepines were generally more potent than the related azirino[1,2-d] [1,4]benzodiazepine derivatives which, however, showed a remarkable anticonvulsant activity. The rank order of potency for anticonvulsant activity was flunitrazepam > diazepam > pinazepam > ABDZ5 > ABDZ4 > prazepam > halazepam > ABDZ1 > ABDZ3 > camazepam > ABDZ6 > ABDZ2. 4. The impairment of locomotor performance following intraperitoneal (IP) administration of the aforementioned derivatives was also evaluated by means of rotarod test. The rank order of potency for impairment of coordinated motor movements was pinazepam > flunitrazepam > diazepam > ABDZ5 > prazepam > halazepam > ABDZ4 > ABDZ3 > ABDZ1 > camazepam > ABDZ2 = ABDZ6. 5. A hypothermic activity was observed after the highest doses of the benzodiazepines studied. 6. The potency of various 1,4-benzodiazepines and azirino[1, 2-d][1,4]benzodiazepines as inhibitors of specific [3H]flumazenil binding to membranes from cerebellum or cortex was evaluated. In general, they inhibited [3H]flumazenil binding at the micromolar range. However, some ABDZ derivatives, although active as anticonvulsants, failed to displace [3H]flumazenil. 7. The azirino[1,2-d] [1,4]benzodiazepine derivatives are more lipophilic than the related benzodiazepines, but the different degree of anticonvulsant activity and impairment of coordinated motor movements cannot be directly related to the lipophilicity of the compounds studied. 8. The pharmacologic actions of ABDZ4 and ABDZ5, which appeared as the most potent anticonvulsants of the azirino[1,2-d] [1,4]benzodiazepine derivatives, were significantly reduced by treatment with flumazenil (8.24 mumol/kg IP) suggesting a clear involvement of benzodiazepine mechanisms in the anticonvulsant activity of these compounds or their metabolites. 9. The anticonvulsant activity of ABDZ4 and ABDZ5 was also evaluated against seizures induced by the two beta-carbolines, methyl beta-carboline-3-carboxylate (beta-CCM) and methyl6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM), in DBA/2 mice. Both ABDZ4 and ABDZ5 gave better protection against the seizures induced by beta-CCM than DMCM, suggesting a preferential action on BDZ1 receptors.

Acoustic Stimulation↗

PubMed1985

Demonstration of benzodiazepine-like molecules in the mammalian brain with a monoclonal antibody to benzodiazepines.

An anti-benzodiazepine monoclonal antibody has been used to demonstrate the existence of benzodiazepine-like molecules in the brain. Immunocytochemical experiments show that these molecules are neuronal and not glial and that they are ubiquitously distributed throughout the brain. Immunoblots indicate the presence of benzodiazepine-like epitopes in several brain peptides. Small benzodiazepine-like molecules were isolated from the brain soluble fraction by immunoaffinity chromatography. They block the binding of agonists, inverse agonists, and antagonists to the neuronal-type benzodiazepine receptor. The neurotransmitter gamma-aminobutyric acid increases the affinity of the benzodiazepine receptor for the purified endogenous molecules. The results indicate that the immunoaffinity-purified molecules behave like the neuronal-type benzodiazepine receptor agonists. The purified molecules, however, do not inhibit the binding of tritiated Ro 5-4864 to the "peripheral-type" benzodiazepine receptor. The results demonstrate the existence of benzodiazepine-like molecules in the brain that bind to the benzodiazepine receptor. These molecules are different from the endogenous benzodiazepine receptor ligands reported by others.

Animals↗

PubMed1993

Labelling of diazepam-sensitive and -insensitive benzodiazepine receptors with [3H]tert-butyl-8-chloro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo [1,5-a][1,4]benzodiazepine 3-carboxylate (ZG-63).

A diazepam-insensitive subtype of benzodiazepine receptor has been identified in the cerebella of several species, including man. t-Butyl-8-chloro-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4] benzodiazepine 3-carboxylate (ZG-63) was recently described as a selective, high affinity ligand at diazepam-insensitive benzodiazepine receptors. This compound was tritiated, and its properties as a radioligand evaluated in rat brain membranes. Consistent with the high affinity and selectivity described for the non-radioactive form of this compound, saturation analyses of [3H]ZG-63 binding to cerebellar diazepam-insensitive and other, diazepam-sensitive benzodiazepine receptors revealed Kd values of 2.6 +/- 0.2 nM and 10.6 +/- 1.4 nM, respectively. The density (Bmax) of cerebellar diazepam-insensitive receptors labelled with [3H]ZG-63 was not significantly different from values obtained with the prototypical diazepam-insensitive receptor ligand [3H]Ro 15-4513, representing approximately 30% of total cerebellar benzodiazepine receptors. [3H]ZG-63 also labelled cortical diazepam-sensitive benzodiazepine receptors, with Bmax values that were not significantly different from those obtained with [3H]flunitrazepam. Diazepam-insensitive benzodiazepine receptors in rat cerebral cortex could be detected with [3H]ZG-63, but the densities of these sites are a very minor component (< or = 5%) of total benzodiazepine receptors. In the presence of GABA, [3H]ZG-63 behaved as a 'gamma-aminobutyric acid (GABA) -positive', 'GABA-negative', and 'GABA-neutral' ligand at cortical diazepam-sensitive receptors, cerebellar diazepam-sensitive receptors, and cerebellar diazepam-insensitive benzodiazepine receptors, respectively. This profile differs from the prototype diazepam-insensitive receptor ligand, [3H]Ro 15-4513. Competition studies demonstrated a very high correlation (r2 = 0.98; P < 0.002) between the potencies of a series of benzodiazepine receptor ligands to inhibit [3H]ZG-63 and [3H]Ro 15-4513 binding to cerebellar diazepam-insensitive receptors. The high affinity and selectivity of [3H]ZG-63 for diazepam-insensitive receptors (diazepam-insensitive/diazepam-sensitive ratio of approximately 0.25) together with a GABA-shift profile which differs from Ro 15-4513 suggests that this compound may be useful in elucidating the function(s) of this benzodiazepine receptor subtype.

Animals↗

PubMed2000

Benzodiazepines for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a potentially disfiguring movement disorder of the orofacial region often caused by use of neuroleptic drugs. A wide range of strategies have been used to help manage TD and, for those who are unable to have their antipsychotic medication stopped or substantially changed, the benzodiazapine group of drugs has been suggested as a useful adjunctive treatment. OBJECTIVES: To determine the clinical efficacy of benzodiazepines for people with neuroleptic-induced tardive dyskinesia (TD) schizophrenia or other chronic mental illnesses. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1995), the Cochrane Schizophrenia Group's Register of trials (1995), EMBASE (1980-1995), LILACS (1982-1995), MEDLINE (1966-1995), PsycLIT (1974-1995), SCISEARCH (1995) and handsearching the references of all identified studies. SELECTION CRITERIA: The inclusion criteria for all randomised studies were that they should focus on people with schizophrenia or other chronic mental illnesses and neuroleptic-induced TD and compare the use of benzodiazepines to placebo or no intervention. DATA COLLECTION AND ANALYSIS: The reviewers extracted the data independently and the odds ratio (95% CI) or the average difference (95% CI) were estimated. The reviewers assumed that people who dropped out had no improvement. MAIN RESULTS: Two trials were able to be included in this review. The results of this review do not allow any confident interpretations on the clinical utility of benzodiazepines for the treatment of neuroleptic-induced TD. From the data combined in this review, benzodiazepines have no distinct advantages over placebo in the treatment of TD. Data on side effects were not reported in the included trials. REVIEWER'S CONCLUSIONS: No clear statement about the efficacy of benzodiazepines drugs, to treat neuroleptic-induced TD, could be provided.

Anti-Anxiety Agents↗