Histamine antagonism

It is a powerful antagonist of histamine, antagonizing its effect on smooth muscle of the bronchioles, bladder and partially the intestines and preventing the dilation of capillaries. Promethazine is used in the treatment of allergic reactions. 

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... 

Cryptolepine has been found to possess anti-inflammatoiy effects in the carrageenan-induced paw edema in rats (27) and Iwu (as cited in Iwu et al 1999) has also reported that the compound has shown histamine antagonism (1). 

NB Cited Marshall PB, Some chemical and physical properties associated with histamine antagonism, Br. J. Pharmacol,... 

Marshall PB, Some chemical and physical properties associated with histamine antagonism, Br. J. Pharmacol., 10, 270-278 (1955). Cited in Perrin Bases 1068 ref. M14. Used glass electrode in cell with liquid junction potentials. 

For the oxatomide-analogues the results of histamine antagonism in vitro, together with the EDsq s for protection from anaphylactic shock and the values of histamine oedema at a standard dose of 2. 5 mg/k.g are summarized in Table III a and b. 

Histamine antagonism in vitro (A q), protection from anaphylactic schock (EDjo) histamine oedema values. 

Comparison with numerous reference compounds in this test indicated that histamine antagonism at the level of the so-called Hi-histamine receptors was sufficient to prevent the lethal shock, but other effects in relation to the release and action of mast cell mediator s may promote the protective activity of a compound. 

Histamine H2 Receptor Antagonists. In 1972 a new class of histamine antagonists was described that was capable of antagonizing histamine-induced gastric acid secretion (6). The H2 antagonists are divided into five stmctural classes, some of which are shown in Table 3. A more complete review can be found in Reference 25. 

Antihistamine. Compound that, by occupying the histamine receptors, antagonizes the effects of histamine. 

Zhang, M., van de Stolpe, A., Zuiderveld, O., and Timmermans, H. (1997). Combined antagonism of leuko-trienes and histamine produces predominant inhibition of allergen-induced early and late phase airway obstraction in asthmatics. Eur. J. Med. Chem. 32 95—102. 

The term antihistamines describes drags which bind to the Hi-histamine receptor and antagonize (block) the histamine effect in Type I allergic responses. 

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. 

Black, JW, Duncan, WAM, Durant, CJ, Ganellin, CR and Parsons, ME (1972) Definition and antagonism of histamine H2 receptors. Nature 236 358-390. 

Comparison of the Antagonism by Burimamide of the Actions of Histamine and Two Related Agonists on Guinea-Pig Atria... 

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