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Biomedical subjects

M Bahro

Publications and source records attributed to M Bahro.

18 recordsLinked to original sources
PubMed1995

Differential cholinergic regulation in Alzheimer's patients compared to controls following chronic blockade with scopolamine: a SPECT study.

The effects of low-dose chronic scopolamine on measures of cerebral perfusion and muscarinic receptors were tested in eight Alzheimer's disease (AD) subjects and eight elderly controls. Single photon emission computed tomography (SPECT) scans using technetium-labelled hexamethypropylene amine oxide (99mTc-HMPAO) to measure cerebral perfusion before and after chronic scopolamine revealed a significant 12% increase in the normal controls (P < 0.01) while the AD subjects showed no significant change. In contrast, the controls showed decreased muscarinic binding as evidenced by 123I-quinuclidinyl-4-iodobenzilate (123I-QNB) labelling after chronic drug (-10%, P < 0.01) whereas the AD subjects showed increased 123I-QNB labelling (+8%, P < 0.05). The difference between AD and control subjects was even more marked when the ratio of I-QNB to HMPAO uptake was compared, pointing to a double dissociation in the SPECT results. These data cannot be explained by group differences in cerebral perfusion alone and suggest a differential sensitivity between AD and elderly controls to chronic cholinergic blockade.

Aged↗
PubMed1995

The effects of scopolamine, lorazepam, and glycopyrrolate on classical conditioning of the human eyeblink response.

Human eyeblink conditioning, a relatively simple form of learning and memory, has previously been shown to be impaired by the central and peripheral anticholinergic scopolamine. The present study compared the behavioral effects of scopolamine with the benzodiazepine lorazepam and a peripherally active anticholinergic, glycopyrrolate. Thirty-six healthy normal volunteers (mean age: 23.7 years) were studied with 12 assigned double-blind to each of three drug conditions (0.5 mg scopolamine IV, 2 mg lorazepam PO, or 0.2 mg glycopyrrolate IV). Subjects underwent classical conditioning of the eyeblink response in which the conditioned stimulus was an 80 dB binaural tone, and the unconditioned stimulus was a 2 psi airpuff to the right eye. Ten trials of unpaired stimulus presentations were followed by 60 paired trials and finally by an extinction period of five tone-alone presentations. An eyeblink response that occurred during the tone but before the airpuff was scored as a conditioned response (CR). Subjects treated with lorazepam (43% mean CRs) and scopolamine (51% mean CRs) exhibited a significantly lower asymptotic level of conditioning than those treated with glycopyrrolate (85% mean CRs; P < 0.01). However, during extinction, lorazepam-treated subjects (35% CRs) showed a lower overall level of responding to the tone than either scopolamine (60% CRs) or glycopyrrolate (62% CRs) treated subjects (P < 0.05). It seems unlikely that these differences could be accounted for by drug-induced alterations in motor responses because there were no significant differences between the three drug conditions in the frequency, latency, or amplitude of unconditioned responses to the airpuff. Overall, our data indicate that scopolamine and lorazepam impair eyeblink conditioning and suggest that some of the effects of benzodiazepines and anticholinergics on learning and memory can be differentiated using this paradigm.

Adult↗
PubMed1995

Benzodiazepine administration induces exogenic psychosis: a case of child abuse.

An 11-year-old boy with psychiatric symptoms was brought to the pediatric clinic by his father. The boy exhibited anxiety, sometimes exaggerating to panic reactions, rage, and disorientation. Because of the boy's behavior it was presumed he was having delusions. Careful physical examination revealed evidence of physical abuse. This article alerts readers to the possible combination of physical abuse and purposeful drug administration.

Aggression↗
PubMed1994

Sleep in depression: the influence of age, gender and diagnostic subtype on baseline sleep and the cholinergic REM induction test with RS 86.

One hundred and eight healthy controls and 178 patients with a major depressive disorder according to DSM-III were investigated in the sleep laboratory after a 7-day drug wash-out period. Subsamples of 36 healthy controls and 56 patients additionally took part in the cholinergic rapid eye movement (REM) sleep induction test with RS 86. Data analysis revealed that age exerted powerful influences on sleep in control subjects and depressed patients. Sleep efficiency and amount of slow wave sleep (SWS) decreased with age, whereas the number of awakenings, early morning awakening, and amounts of wake time and stage 1 increased with age. REM latency was negatively correlated with age only in the group of patients with a major depression. Statistical analysis revealed group differences for almost all parameters of sleep continuity with disturbed indices in the depressed group. Differences in SWS were not detected. REM latency and REM density were altered in depression compared to healthy subjects. Sex differences existed for the amounts of stage 1 and SWS. The cholinergic REM induction test resulted in a significantly more pronounced induction of REM sleep in depressed patients compared with healthy controls, provoking sleep onset REM periods as well in those depressed patients showing baseline REM latencies in the normal range. Depressed patients with or without melancholia (according to DSM-III) did not differ from each other, either concerning baseline sleep or with respect to the results of the cholinergic REM induction test. The results stress the importance of age when comparing sleep patterns of healthy controls with those of depressed patients. Furthermore they underline the usefulness of the cholinergic REM induction test for differentiating depressed patients from healthy controls and support the reciprocal interaction model of nonREM-REM regulation and the cholinergic-aminergic imbalance hypothesis of affective disorders.

Adolescent↗
PubMed1994

Cholinergic neurotransmission, REM sleep and depression.

It is known from animal experiments that the regulation of REM and Non-REM sleep is governed by cholinergic and serotonergic/adrenergic neurons in the brain stem. Cholinergic neurons in the gigantocellular field of the tegmentum seem to be responsible for the triggering and maintenance of REM sleep. These findings are of special interest for interpreting abnormalities of REM sleep in depression. Psychiatric sleep research in the last two decades has demonstrated that an early onset of REM sleep and heightened REM density frequently occurs in patients suffering from depression. Extrapolating from animal data on REM sleep regulation, the premature onset of REM sleep in depression may be interpreted as the consequence of a central nervous cholinergic overactivity or muscarinic supersensitivity. In our experimental work we have tested assumptions of the so-called reciprocal interaction model of NonREM and REM sleep by cholinergic/anticholinergic stimulation strategies of sleep in healthy subjects. Furthermore, the impact of cholinergic stimulation on sleep in depression, healthy control subjects and other psychopathological conditions was investigated. These studies demonstrated that the most pronounced REM sleep response to cholinergic stimulation occurred in depression.

Adolescent↗
PubMed1994

[REM sleep parasomnia].

The parasomnias consist of a heterogenous group of sleep behaviour disorders with different etiologies and various symptomatologies. By employing polysomnography and the simultaneous video recording of behaviour during sleep, it is possible to associate behavioral disturbances during sleep with specific sleep stages. In the present case study, a patient with a REM (rapid eye movement) sleep behaviour disorder is discussed. This rare form of parasomnia is characterized by motor enactment of vivid and striking dreams. Underlying disease in the present case involved bilateral lacunar ischemic infarcts in the brain stem. Under the combined psychotropic medication of carbamazepine and amitriptyline, the behaviour disorder during REM sleep remitted markedly.

Amitriptyline↗
PubMed1993

REM sleep parameters in the discrimination of probable Alzheimer's disease from old-age depression.

Thirteen dementia of the Alzheimer type (DAT) patients and fifteen old-age major depressive disorder (OAD) patients were investigated by polysomnography. The sleep was recorded during two nights after a 1 week wash-out period of psychotropic drugs. No statistically significant differences between the two groups were found concerning sleep continuity or architecture. The amount of REM sleep was significantly lower in DAT in comparison with OAD patients (11.7% verses 18.5%). Also, total REM density as well as the density of the first REM period were significantly lower in the DAT compared with the OAD patient group (15.8% verses 32.5%, 14.9% verses 38.1%, respectively). REM latency did not differ between both groups. Because REM latency is known from other studies to be shortened in depressed patients due to a cholinergic hyperactivity, the opposite finding, i.e., prolongation of REM latency, was expected for DAT patients. This assumption, however, could not be confirmed in the present study. It is concluded that REM density may better differentiate between DAT and OAD.

Aged↗
PubMed1993

Acute exogenic psychosis following oral ingestion of 2 mg lormetazepam in an eleven-year-old boy.

After oral ingestion of 2 mg lormetazepam given by his mother, an 11-year-old boy suffered from severe adverse effects. Main symptoms were disorientation, restlessness, amnesia, anxiety, hostility, and rage reactions. Paranoid ideations and impaired perception were concluded from strange reactions and remarks of the child. Symptoms are similar to the van der Kroef syndrome described after the use of rapidly eliminated high-potency benzodiazepines. This case demonstrates drug abuse on the part of parents wishing to induce sleep in their children.

Adolescent↗
PubMed1993

The effect of carbamazepine on endocrine and sleep EEG variables in a patient with 48-hour rapid cycling, and healthy controls.

Carbamazepine treatment of a patient with 48-hour rapid cycling led to a dampening of mood cycling, and prolonged rapid eye movement (REM) sleep latency. No effect on central alpha-receptors as measured by growth hormone (GH) secretion after clonidine stimulation or on spontaneous 48-hour GH secretion was observed. In 12 healthy subjects given 400 mg carbamazepine daily for a period of 5 days, improved sleep continuity and increased slow-wave sleep occurred with treatment. REM sleep percentage and REM latency remained uninfluenced, whereas REM density decreased. GH secretion after clonidine stimulation was not altered. Data from the single-case longitudinal study emphasize that carbamazepine is effective in treating rapid-cycling affective psychosis. Furthermore, neuroendocrine and sleep EEG data from the study in healthy subjects indicate a different profile of action for carbamazepine compared to most other antidepressants or antimanic drugs.

Adult↗
PubMed1991

Regional and laminar distributions of alpha 1-adrenoceptors and their subtypes in human and rat hippocampus.

The distributions of the alpha 1-adrenoceptor and its subtypes (alpha 1A and alpha 1B) in human and rat hippocampus are analysed by quantitative receptor autoradiography. alpha 1-Adrenoceptors are labelled by [3H]prazosin. The alpha 1A subtype is visualized by [3H]prazosin after irreversible blockade of alpha 1B adrenoceptors with chloroethylclonidine or directly by [3H]5-methyl-urapidil. The alpha 1B subtype is investigated by [3H]prazosin binding in the presence of the alpha 1A antagonist 5-methyl-urapidil. Considerable differences in the regional and laminar patterns of alpha 1-adrenoceptors are found between rat and human hippocampi. The rat hippocampus is characterized by a low overall density and a rather homogeneous regional and laminar distribution. This is in contrast to the human pattern, which shows a much higher overall level of alpha 1 receptor density and a restriction of alpha 1 receptors to the CA3 region of Ammon's horn and the dentate gyrus. Moreover, alpha 1A and alpha 1B receptors of the human hippocampus are differentially distributed with the alpha 1A subtype concentrated in the hilus and lucidum layer of CA3, and the alpha 1B subtype concentrated in the molecular layer of the dentate gyrus. Additionally, the distribution of alpha 1 receptors is compared with the distribution of 5-hydroxytryptamine 1A receptors. The subtype specific pattern is correlated with the distribution of glutamatergic systems in the human (but not in the rat) hippocampus. alpha 1A Receptor localization coincides with the target area of the mossy fibre system, and alpha 1B receptors are preferentially localized in the target area of the hippocampal associational fibres and partly of the perforant pathway. This result points to possible interactions between noradrenaline- and glutamate-mediated neurotransmission differentiated by topographically segregated alpha 1-adrenoceptor subtypes.

Adrenergic alpha-Antagonists↗
PubMed1988

Short-term stimulation of cellular autophagy by furosemide in the thick ascending limb of Henle's loop in the rat kidney.

In an effort to investigate the functional relationship between cell-specific work and intracellular degradative processes, the effect of furosemide on cellular autophagy was investigated in two different portions of the nephron, namely, the thick ascending limb of Henle's loop (TAL), which is a main target of this drug, and the proximal convoluted tubule (PCT) as a reference structure. Eight male adult rats were treated with furosemide (60 mg/kg body weight, s.c.). Eight control animals received physiological saline. 1 to 4 h after the injections the animals were killed by perfusion fixation. Small specimens of kidney tissue from the inner stripe of the outer medulla and from the outer cortex were processed for electron microscopy; they were investigated morphometrically for volume fraction and numerical density of autophagic vacuoles (AVs). A significant increase of both parameters (volume fraction: 0.42 x 10(-4) to 1.09 x 10(-4); numerical density: 4.2 x 10(5)/mm3 to 15.5 x 10(5)/mm3) was seen under the influence of furosemide in TAL cells, whereas PCT cells did not show a significant increase in volume fraction or any increase in numerical density of AVs. These data suggest that the functional unloading of TAL, via blocking of the Na+-2Cl- -K+ co-transport by furosemide, results in adaptative "structural unloading", i.e., an increased sequestration of cytoplasmic components into AVs, within a short-time interval.

Animals↗
PubMed1987

Short-term inhibition of cellular autophagy by isoproterenol in the submandibular gland.

The present study examines the short-term (i.e. 10 min after injection) influence of isoproterenol on cellular autophagy in the rat submandibular gland. The volume fraction of autophagic vacuoles was significantly reduced, suggesting that an anticatabolic reaction, namely inhibition of cellular autophagy, is an early and significant event in the growth of the submandibular gland which is known to occur with long-term isoproterenol treatment.

Animals↗
PubMed1987

Short-term stimulation by propranolol and verapamil of cardiac cellular autophagy.

The influence of propranolol and verapamil, i.e. two cardiodepressant drugs differing in their pharmacological actions, on cellular autophagy in the left ventricular myocardium of the rat was investigated. In the first experimental series 10 animals were given propranolol subcutaneously (3 mg/kg body weight). Ten controls received physiological saline. In the second series 8 animals were treated with verapamil subcutaneously (9 mg/kg body weight) and 8 controls with physiological saline. Two to 4 h after the injections in the first series and 1 3/4 to 3 h in the second series retrograde perfusion fixation was carried out via the abdominal aorta with a paraformaldehyde-glutaraldehyde mixture. Myocardial tissue from the left anterior wall was processed for electron microscopy and was morphometrically evaluated for volume fraction and numerical density of early stages of autophagic vacuoles (AVs). Propranolol and verapamil significantly increased the AV volume fraction 4.3- and 2.7-fold, respectively. The numerical density was increased by the two drugs, although to a lesser degree (2.3-fold, and 1.7-fold, respectively). As verapamil affects neither the beta-adrenoreceptors nor the intracellular levels of the second messenger cAMP, the only common denominator for the stimulation of cellular autophagy seems to be the cardiodepressive effect of the two drugs. The data suggest that the rise in cellular autophagy is an early regulatory step in the adaptation of heart muscle mass to reduced work load.

Animals↗
PubMedDate not supplied

Involvement of autophagic degradation in ACTH-induced skeletal muscle atrophy.

Intracellular autophagic breakdown was investigated in skeletal myocytes undergoing atrophy under the influence of ACTH. Adult male Sprague-Dawley rats received s.c. injections of ACTH (12.5 U/kg body wt) or physiological saline as control twice daily. 5 experimental and 5 control animals were sacrificed by perfusion fixation after 6, 9, and 12 days of treatment. While the weight of the left pectoralis minor muscle decreased significantly in the ACTH-treated animals compared with controls, the volume fraction of autophagic vacuoles, as determined by quantitative electron microscopy, increased significantly after 9 days (2.6-fold) and 12 days (2.9-fold) in the atrophying skeletal myocytes of experimental animals compared with controls. Only non-myofibrillar components were detected as contents of autophagic vacuoles. Since, however, the ratio of myofibrils to other cytoplasmic components remained constant, the degradation of myofibrils seems to occur via a non-lysosomal pathway. The data suggest that the breakdown of cytoplasmic components by cellular autophagy is important for the development of skeletal muscle atrophy as observed following long-term ACTH treatment or in Cushing's syndrome.

Adrenocorticotropic Hormone↗