Histamine Hj receptors

Another antiulcer histamine Hj receptor antagonist containing a thiazole moiety is zalb-dine (131) Its synthesis can be accomplished readily by brominating 4 acetyl 2 methylimidazole (129) to give haloketone 130 Displacement with amidinothiourea completes the synthesis of zaltidme (131) via a displacement cyclodehydration sequence [45]... 

We examined the effects of selective activation of histamine Hj receptors on coronary hemodynamics in two groups patients with atypical chest pain and normal coronary arteries, and patients with vasospastic angina [48]. Selective Hj receptor stimulation was achieved by infusing histamine intravenously (0.5 pg/kg/min) for 5 min after pretreatment with cimetidine to antagonize the H2 receptors. Heart rate was kept constant (100 beats/min) by coronary sinus pacing. 

Studies of the histamine Hj-receptor antagonists substances were extracted from 97... 

Histamine Hj receptor Antagonist Acute (central nervous system) Sedation Diphenhydramine27... 

Histamine Hj receptor HIstamlnergic neurons, eosinophils, DC, monocytes Low expression in peripheral tissues Enhanced Ca +, MAP kinase, inhibition of cAMP ... 

Histamine H receptor Histamine Hj receptor Histamine H3 receptor Histamine H4 receptor... 

Banu Y. Watanabe T Augmentation of antigen receptor-mediated responses by histamine Hj receptor signaling. J Exp Med 1999 189 673-682. 

Del Valle J. Gantz I Novel insights into histamine Hj receptor biology. Am J Physiol 1997 273 G987-G996. 

Fujikura T, Shimosawa T, Yakuo I Regulatory effect of histamine Hj receptor antagonist on the expression of messenger RNA encoding CC chemokines in the human nasal mucosa. J Allergy Chn Immunol 2001 107 123-128. 

Gantz I, Schaffer M, DelValle J Molecular cloning of a gene encoding the histamine Hj receptor. Proc Natl Acad Sci USA 1991 88 5937. 

Lovenberg TW, Roland BL, Wilson SJ, Jiang X, Pyati J, Huvar A, et al Cloning and functional expression of the human histamine Hj receptor. Mol Pharmacol 1999 55 1101-1107. 

Belladonna alkaloids have an extremely broad pharmacological spectrum. In addition to their ability to block M-receptors, atropine and scopolamine also act on other receptors, thus showing corresponding effects. They can only block nicotinic cholinergic receptors, however, in significantly larger doses than those used in clinics. Atropine also exhibits properties of local anesthetics and histamine (Hj) receptor blockers. Atropine and... 

Two membrane-receptive binding sites called and receptors mediate the pharmacological effect of histamine. Hj receptors are located in smooth muscle of vessels, and bronchial and gastrointestinal tract, while H2 receptors are found in the walls of the stomach, myocardium, and certain vessels. 

Verongula gigantea Hyatt, Verongida, Porif. verongamine (bromotyrosine metabolite)/histamine Hj receptor antagonist Mierzwa 1994... 

SSRIs were developed in an attempt to formulate reuptake-blocking drugs that lacked the troublesome side effects of TCAs. Of the five pharmacological properties of TCAs—blockade of muscarinic receptors, blockade of histamine Hj receptors, blockade of aj-adrenergic receptors, norepinephrine reuptake blockade, and serotonin reuptake inhibition—only the last remains intact in SSRIs. This selectivity has... 

Risperidone, a novel benzisoxazole derivative, is an atypical antipsychotic medication that combines dopamine D2 receptor antagonism with potent 5-HT2 receptor antagonism. Risperidone has a higher affinity for dopamine D2 receptors than does clozapine. Risperidone also antagonizes dopamine Dj and D4 receptors, aj- and a2-adrenergic receptors, and histamine Hj receptors. Although the optimal dose of risperidone in North American trials was 6 mg/day, subsequent clinical experience has indicated that most patients do well at lower doses of 3-6 mg/day, and elderly patients may require doses as low as 0.5 mg/day. Unlike other atypical antipsychotics. 

G. J. Durant (1979). Chemical aspects of histamine Hj-receptor agonists and antagonists. In ... 

Fixed dose combination of histamine Hj-receptor antagonists with antacids except for those combinations approved by the Drugs Controller, India. 

Sorba, G. Tertuik, W. Ganellin, C. R. Synthesis and authentication of iodoazidophenpyr-amine, a photoaffmity reporter ligand previously used for histamine Hj-receptor labelling. Arch. Pharm. (Weinheim) 1995, 328, 677-680. 

Clozapine, olanzapine, and quetiapine display significant affinity to histamine Hj receptors, and it is widely accepted that some side effects of these agents (e.g., weight gain liability, sedation) are attributed to their histamine antagonism... 

Histamine Hj-receptor antagonists bind to Hj receptors without activating them, preventing histamine binding and action. They are more effective in preventing the histamine response than in reversing it. 

Treatment. Remove the cause use cooling applications and antipruritics use a histamine Hj receptor blocker systemically for acute urticaria give an adrenal steroid for severe cases. 

Other drugs. Ketotifen is a histamine Hj-receptor blocker which may also have some antiasthma effects but its benefit has not been conclusively demonstrated. In common with other antihistamines it causes drowsiness. 

Antimuscarinic drugs (including those classed primarily as histamine Hj receptor antagonists) are described in Chapters 21 and 29. Drugs with antimuscarinic activity probably act both centrally... 

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