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Biomedical subjects

C Kamei

Publications and source records attributed to C Kamei.

At least 73 records · Page 4Linked to original sources
PubMed1997

Effects of intracerebroventricular injection of histamine on memory deficits induced by hippocampal lesions in rats.

The influence of bilateral hippocampal lesions on active avoidance response was studied in rats, as well as the effect of intracerebroventricular (i.c.v.) injection of histamine on memory deficits caused by hippocampectomy. Retardation of learning acquisition was produced by lesioning of the bilateral dorsal hippocampus in active avoidance response. Memory retention was also impaired by hippocampectomy. Although locomotor activity and rearing behavior measured by open-field test increased after hippocampal lesions, there was no relation between impairment of learning and increase in exploratory behavior. I.c.v. injection of histamine and i.p. injection of histidine resulted in an improvement of memory deficits (not only learning acquisition but also memory retrieval) induced by hippocampal lesions in rats. Histamine contents of the hippocampus and hypothalamus decreased after hippocampectomy, and a decrease in histamine contents of both areas was restored by histamine (i.c.v.) and histidine (i.p.) injection. In addition, a close relationship was found between decrease in response latency of avoidance response and an increase in histamine content of the hippocampus and hypothalamus after histamine injection.

Animals↗
PubMed1997

Effect of Apafant on bronchial hyperresponsiveness and down-regulation of beta-adrenoceptors induced by endotoxin in guinea pigs.

Intraperitoneal injection of endotoxin resulted in bronchial hyperreactivity to histamine in guinea pigs. In addition, endotoxin (lipopolysaccharide, LPS) caused a decrease in the relaxation of the lung parenchymal strips induced by the beta-adrenoceptor agonist, isoproterenol (isoprenaline), and a reduction in the number of beta-adrenergic binding sites in the lung membrane preparation in guinea pigs. Apafant (CAS 105219-56-5, WEB 2086) was effective in the prevention of endotoxin-induced changes, i.e., bronchial hyperreactivity to histamine, a decrease in the relaxation of lung parenchymal strips induced by isoproterenol and a reduction in the number of beta-adrenergic binding sites in the lung membrane preparation in guinea pigs. Ketotifen and ozagrel also prevented the bronchial hyperresponsiveness and endotoxin-induced deterioration of the beta-adrenergic system. No remarkable effect was observed with cromolyn sodium and salbutamol in the bronchial hyperreactivity to histamine induced by endotoxin in guinea pigs. Cromolyn sodium also caused no influence on the down-regulation of beta-adrenoceptors.

Adrenergic beta-Agonists↗
PubMed1997

Effects of apafant on PAF-induced downregulation of beta-adrenoceptors in guinea pigs.

We examined the effects of platelet-activating factor (PAF) on beta-adrenoceptors and the functional response to isoproterenol in guinea pig parenchymal strips. PAF caused a reduction in the relaxation of guinea pig lung parenchymal strips induced by the beta-adrenoceptor agonist, isoproterenol. In addition, PAF decreased the density of beta-adrenoceptors in guinea pig lung without any change in the affinity. Apafant, a potent PAF antagonist, inhibited the above changes, indicating that it inhibited the downregulation of beta-adrenoceptors. These findings suggest that apafant may be effective in nonspecific airway hyperreactivity in asthma.

Adrenergic beta-Agonists↗
PubMed1997

Role of substance P in experimental allergic conjunctivitis in guinea pigs.

The role of substance P in experimental allergic conjunctivitis induced by egg albumin was investigated with guinea pigs. Increase in vascular permeability of the conjunctiva induced by antigen was significantly inhibited after repeated application of capsaicin. Substance P contents in the conjunctiva of guinea pig were decreased by topical instillation of antigen to the eyes, suggesting that substance P was released from the conjunctiva due to antigen-antibody reaction. Moreover, subconjunctival injection of substance P resulted in a dose-related conjunctivitis, and vascular permeability in the conjunctiva was also increased by substance P. In substance P-induced conjunctivitis, a significant edema was observed in the bulbar and palpebral conjunctiva, but no hyperemia was noted in all instances. Histamine contents of the conjunctiva and tears were not influenced by subconjunctival injection of substance P. However, topical application of antigen and subconjunctival injection of compound 48/80 caused a significant decrease in histamine content, and content of tear was increased by both treatments. An increase in vascular permeability induced by antigen application was significantly inhibited by intravenous injection of FK-888, which is a specific and potent NK1 receptor antagonist. From these results, it is suggested that substance P is responsible for allergic conjunctivitis to some extent, and the conjunctival hyperpermeability induced by substance P occurs through NK1 receptor on the blood vessels, rather than by the direct action on the conjunctival mast cells during allergic conjunctival reactions.

Animals↗
PubMed1996

Mechanism of Bradykinin-induced histamine release from rat peritoneal mast cells.

Bradykinin at concentrations higher than 2 microM caused a significant histamine release from rat peritoneal mast cells when extracellular Ca2+ was removed from the medium. Under the same experimental conditions, bradykinin increased Ca2+ release from the intracellular Ca store of the rat peritoneal mast cells, and a clear relationship was observed between the magnitude of histamine release and an increase in fluorescence intensity. Addition of Ca2+ to the medium resulted in an inhibition of the response to bradykinin in a concentration-dependent manner. Almost the same results were obtained when Mg2+, Ba2+ and La3+ were added to the medium. Neither B1 nor B2 antagonists caused significant antagonistic effects on histamine release induced by bradykinin. However, B2 antagonists caused a histamine release of the same potency as bradykinin when applied alone. These results indicate that bradykinin-induced histamine release is not attributable to a bradykinin receptor.

Animals↗
PubMed1996

Epileptogenic activity induced by combined treatment with antiinflammatory drugs and enoxacin and its inhibition by a calcium antagonist, nicardipine.

Epileptogenic activity induced by combined treatment with antiinflammatory drugs and enoxacin was investigated in chronic electrode-implanted rats. Ferubinac ethyl and aspirin DL-lysine showed a spike and wave complex in EEG without showing remarkable behavioral changes when they were injected intraventricularly, although a relatively high dose was needed. Enoxacin, on the other hand, elicited potent epileptogenic activity characterized by uninterrupted high voltage spike and wave complex at doses of 50 and 100 micrograms. At the same time, rats showed hyperactivity, jumping and violent convulsion. Combined treatment with enoxacin (p.o.) and ferubinac ethyl (i.v.) caused potent epileptogenic activity characterized by uninterrupted burst of high voltage spike and wave complex. Behaviorally, animals showed forelimb clonus, head nodding and generalized convulsion. High voltage spike and wave complex was also observed after combined treatment with enoxacin (i. vent.) and ferubinac ethyl (i.v. or i. vent.) in association with hyperactivity and jumping and violent convulsion. Nicardipine remarkably inhibited epileptic seizures induced by combined treatment with enoxacin (p.o.) and ferubinac ethyl (i.v.). It is concluded that simultaneous treatment with enoxacin and ferubinac ethyl produced epileptogenic activity when injected intraventricularly, and nicardipine inhibited convulsions induced by combined use of enoxacin (p.o.) and ferubinac ethyl (i.v.).

Animals↗
PubMed1996

Effect of the new antiallergic agent olopatadine on EEG spectral powers in conscious rats.

The central effect of olopatadine (((Z)-11-[3-dimethylamino)propylidene)-6, 11-dihydrodibenz[b,e]oxepin-2-acetic acid hydrochloride, CAS 140462-76-6, KW-4679) was studied in comparison with those of ketotifen and doxepin using spontaneous EEG and EEG spectral powers in conscious rats. Both ketotifen (20 mg/kg p.o.) and doxepin (20 mg/kg p.o.) caused drowsy patterns in spontaneous EEG characterized by slow waves of high amplitude at the frontal cortex, occipital cortex and amygdala, and by disappearance of the regularity in theta waves recorded from the hippocampus. In EEG spectral powers, both drugs caused a significant increase in the power densities of the delta band recorded from the frontal cortex, occipital cortex and amygdala. On the contrary, no visible changes were elicited by the treatment with olopatadine (20 mg/kg p.o.) in both spontaneous EEG and EEG spectral powers recorded from the frontal cortex, occipital cortex, hippocampus and amygdala. These results indicate that olopatadine provides no remarkable effect on the central nervous system.

Animals↗
PubMed1995

Effects of certain antiallergic drugs on experimental conjunctivitis in guinea pigs.

Effects of certain antiallergic drugs on experimental conjunctivitis were studied with guinea pigs. Chlorpheniramine, ketotifen and levocabastine were effective in inhibiting histamine- and antigen-induced conjunctivitis in guinea pigs. By contrast, amlexanox was only effective in inhibiting antigen-induced conjunctivitis. Topical application of antigen released 46.5 +/- 3.8% of histamine from the conjunctiva in sensitized guinea pigs. Both levocabastine and amlexanox were effective in inhibiting conjunctival histamine release induced by antigen application. Lacrimal histamine contents were also increased after challenge. The increase in the histamine content of tears was inhibited by pretreatment with levocabastine and amlexanox, but no significant effect was observed with chlorpheniramine and ketotifen. From these findings, it is concluded that certain antiallergic drugs, but not amlexanox, exhibited potent inhibition on experimental conjunctivitis in guinea pigs. In addition, it has been established that measurement of histamine in the conjunctiva and tears as well as observation of conjunctivitis syndromes are useful for evaluating the effectiveness of antiallergic drugs on various kinds of allergic conjunctivitis in clinical situations.

Animals↗
PubMed1995

Effect of (Z)-11-[3-(dimethylamino) propylidene]-6,11-dihydrodibenz[b,e]oxepin-2-acetic acid hydrochloride on experimental allergic conjunctivitis and rhinitis in rats and guinea pigs.

The effect of KW-4679 (Z)-11-[3-(dimethylamino) propylidene]-6,11-dihydrodibenz [b,e] oxepin-2-acetic acid hydrochloride, CAS 140462-76-6; proposed INN: olopatadine) on experimental conjunctivitis and rhinitis was studied in comparison with that of ketotifen (CAS 34580-14-8) using guinea pigs and rats, respectively. KW-4679 was effective in inhibiting the antigen- and histamine-induced conjunctivitis by both oral and topical administrations. These effects of KW-4679 were somewhat more potent than those of ketotifen. KW-4679 as well as ketotifen was more effective in inhibiting the histamine-induced conjunctivitis than that seen in antigen-induced conjunctivitis when they were given topically. KW-4679 inhibited the increased dye leakage into the nasal cavity induced not only by antigen in actively sensitized rats but also by histamine perfusion in non-sensitized rats by oral and topical administrations. Similar to ketotifen, the effect of KW-4679 on histamine-induced increase in dye leakage was almost same as that induced by antigen. The potency of KW-4679 was higher than that of ketotifen in the increased dye leakage induced by both antigen and histamine perfusion.

Administration, Oral↗
PubMed1995

Effect of loratadine on immediate and delayed type hypersensitivity reactions.

Loratadine (CAS 79794-75-5) was effective in inhibiting the contractions of the ileum induced by histamine in guinea pigs. The drug also caused an anti-acetylcholine, anti-serotonin and anti-leukotriene D4 (LTD4) effect. In addition, loratadine inhibited the synthesis of leukotrienes more potently than ketotifen. On the other hand, in in vitro studies of histamine release from rat peritoneal mast cells induced by compound 48/80 or lung fragments in actively sensitized guinea, pigs, loratadine elicited a significant inhibition at a concentration of 5 mumol/l. In ex vivo studies, the drug inhibited histamine release from lung fragments induced by concanavalin A, and significant effect lasted for 24 h when the drug was administered at a dose of 20 mg/kg. The drug inhibited LTD4 release as well as histamine from lung fragments in actively sensitized guinea pigs. Loratadine inhibited not only 45Ca uptake into the rat peritoneal mast cells but also Ca2+ release from the intracellular Ca store induced by compound 48/80 or A23187. Loratadine increased cAMP content in rat lung preparation while decreasing cGMP content. Loratadine caused no significant change in order parameter and phospholipase A2 activity. The drug was more potent than ketotifen and terfenadine in inhibiting antigen-induced increase in airway resistance in guinea pigs. In addition, the effect of loratadine on airway resistance was sustained for 12 h. Loratadine inhibited an increase in dye leakage into the nasal cavity in rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1995

Effects of intracerebroventricular injection of histamine and its related compounds on rectal temperature in mice.

Effects of intracerebroventricular injection of histamine and its related compounds on rectal temperature were studied in mice. Histamine (0.1-1.0 mu g) and histidine (500-1,000 mg/kg) caused a dose-related hypothermia. H1 agonist, 2-methylhistamine and 2-thiazolylethylamine also displayed a dose-dependent hypothermia. In addition, H2 agonists, 4-methylhistamine and dimaprit elicited a decrease in body temperature. Preinjection of not only H1-antagonists (diphenhydramine and chlorpheniramine) but also H2 antagonists (cimetidine and ranitidine) abolished histamine-induced hypothermia. Either intracerebroventricular or intraperitoneal injection of thioperamide, a histamine H3 antagonist, showed hypothermia. The hypothermic effect produced by intracerebroventricular injection of thioperamide was significantly blocked by (R)-alpha-methylhistamine, a selective H3 agonist. In addition, the effect induced by thioperamide was inhibited by H1 and H2 antagonists, indicating that the H3 receptor also participates in histamine-induced hypothermia.

Animals↗
PubMed1994

Long-term perfusion of the cerebroventricular system of dogs without leakage to the peripheral circulation.

Methods developed previously for studying the effect of cerebroventricular injection or ventriculocisternal perfusion of test substances are unsatisfactory because the test substance is not confined to the central compartment. Most likely the test substance enters the peripheral circulation via the arachnoid villi. The purpose of this paper is to describe a method for perfusing the cerebroventricular system of conscious dogs without passage of test substances to the peripheral circulation. With the method described, the mean (+/- SE) cerebroventricular pressure in conscious dogs was 7.4 +/- 0.8 cmH2O (n = 16), and the mean (+/- SE) production of cerebrospinal fluid (CSF) was 25 +/- 0.3 microliter/min (n = 16). Endogenously occurring migrating myoelectric complexes (MMCs) of the small intestine were recorded in dogs before catheters were implanted in the left and right lateral ventricles and the fourth ventricle and after catheter implantation during cerebroventricular perfusion with artificial CSF alone or with CSF containing sulfated (S-CCK-OP) or nonsulfated cholecystokinin octapeptide (NS-CCK-OP). Only cerebroventricular perfusion with S-CCK-OP (1.2 pmol.kg-1.min-1; n = 20) replaced spontaneously occurring MMCs with a fed-like pattern of myoelectric activity. The results suggest that replacement of the fasting pattern of myoelectric activity with a fed-like pattern in the fasted dog was mediated by CCK-A receptors located in one or more brain nuclei surrounding the third ventricle.

Animals↗
PubMed1994

Changes in self-stimulation response during chronic morphine treatment and after withdrawal of morphine in rats.

Morphine (5-20 mg/kg, s.c.) dose-dependently inhibited the hypothalamic self-stimulation response 1-2 hr after administration of the drug. Thereafter, slight increase in the self-stimulation response was seen 4-8 hr after drug administration. The depressant effect induced by 10 mg/kg, s.c. of morphine on the self-stimulation response was antagonized by 1 mg/kg, s.c. of levallorphan. Repeated administration of morphine (10 mg/kg, s.c.) resulted in an increase of the self-stimulation response. The self-stimulation response rate was increased significantly 24 and 48 hr after withdrawal of morphine in chronic-morphine-treated rats; In these rats, the initial dose of morphine (10 mg/kg, injected s.c. twice daily 7 days a week) was increased gradually until at the end of 5 weeks, each dose was 50 mg/kg, s.c.

Animals↗
PubMed1994

The role of ions on histamine-induced depolarization in isolated guinea pig adipocytes.

Effects of ions on histamine (Hi)-induced depolarization were studied in guinea pig adipocytes. Depolarization induced by Hi in guinea pig adipocytes was decreased by removal of K+ from the medium or pretreatment with ouabain at concentrations that showed no significant effect themselves. The decrease in membrane potentials induced by Hi was also abolished potently by replacement of Na+ by choline or pretreatment with tetrodotoxin at a concentration that caused no significant action alone. Pretreatment with monensin at a concentration lower than that eliciting the action resulted in a potentiation of Hi-induced depolarization. The depolarization induced by Hi was not affected by the presence of Ca2+ in the medium or pretreatment of the cells by diltiazem.

Adipocytes↗
PubMed1994

Effects of antiallergic agents including levocabastine on experimental rhinitis in rats.

Topical application of levocabastine hydrochloride (-)-[3S-[1(cis)-3 alpha,4 beta]]-1-[4-cyano-4-(4-fluorophenyl) cyclohexyl]-3-methyl-4-phenyl-4-piperidinecarboxylic acid monohydrochloride, inhibited the increase in dye leakage into the nasal cavity induced not only by antigen in actively sensitized rats but also by histamine in non-sensitized rats. The potency of levocabastine was stronger than that of ketotifen in inhibiting the increase of dye leakage in both cases. In addition, levocabastine as well as ketotifen exerted a more potent inhibition of the dye leakage induced by histamine than that induced by antigen. Levocabastine also exerted a significant inhibition on the dye leakage induced by substance P; again the effect of levocabastine was more potent than that of ketotifen. On the other hand, levocabastine elicited no remarkable influence on the dye leakage induced by either acetylcholine or platelet activating factor. However, ipratropium and (RS)-2-methoxy-3-(octadecylcarbamoyloxy)propyl 2-(3-thiazolio)ethyl phosphate were effective when the corresponding agonists were perfused, respectively.

Acetylcholine↗
PubMed1994

Inhibitory effect of epinastine on bronchoconstriction induced by histamine, platelet activating factor and serotonin in guinea pigs and rats.

Effects of epinastine ((+/-)-3-amino-9,13b-dihydro-1H-dibenz[c,f]imidazo[1,5-a]azepine hydrochloride, WAL 801 CL, CAS 80012-43-7) and reference drugs on bronchoconstriction induced by histamine, platelet activating factor (PAF) and serotonin were studied in guinea pigs and rats. Oral administration of epinastine resulted in a potent inhibition on bronchoconstriction induced by all three bronchoconstrictor agents, and especially, an inhibitory effect on histamine-induced response was remarkable. The effect of epinastine was stronger than that of ketotifen in inhibiting the responses induced by both PAF and serotonin. However, the extent of inhibition in the latter was less remarkable than that seen after histamine. Azelastine was 1.36-4.57 times less potent than epinastine in inhibiting the bronchoconstriction induced by either bronchospasmogen. Although promethazine displayed inhibitory effects on the responses induced by histamine, PAF and serotonin, the inhibiting potency was distinctly inferior to that of epinastine.

Airway Resistance↗
PubMed1993

Influence of histamine depletion on learning and memory recollection in rats.

To clarify the role of endogenous histamine in learning and memory, the effect of alpha-fluoromethylhistidine on active avoidance response in rats was studied. alpha-Fluoromethylhistidine (20-100 mg/kg or 10-50 micrograms) significantly (P < 0.05 or P < 0.01) prolonged the response latency in active avoidance response when administered by either intraperitoneal or intracerebroventricular injection. These effects were dose-related and long lasting. A prolongation of the response latency induced by an intraperitoneal injection of alpha-fluoromethylhistidine (100 mg/kg) was antagonized by intracerebroventricular injection of histamine (10 and 20 ng) in a dose-dependent manner. In addition, the acquisition of this response was retarded by a consecutive intracerebroventricular injection of alpha-fluoromethylhistidine (50 micrograms), whereas histamine (100 ng) facilitated the response acquisition when administered by the same route. Both intraperitoneal (100 mg/kg) and intracerebroventricular injection of alpha-fluoromethylhistidine (50 micrograms) significantly (P < 0.05 or P < 0.01) decreased the brain histamine content, especially in the hippocampus and hypothalamus. When alpha-fluoromethylhistidine (50 micrograms) was injected intracerebroventricularly, there is a high correlation between a prolongation of the response latency and a decrease in histamine content of these brain areas. Based on these findings, it was concluded that an intimate relation may exist between a prolongation of response latency in the active avoidance response and a decrease in the brain histamine content; endogenous histamine may play an important role in learning and memory recollection in rats.

Animals↗