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The effects of cimetidine on histamine atrial chronotropic receptor activity.
Agents Actions. 1982 Oct; 12(4):425-30.AA

Abstract

Clinically useful histamine antagonists have been reported to be specific for H1- or H2-receptors. However, data is accumulating that the specificity of those agents may be relative. This study was undertaken in an attempt to clarify this point. Histamine stimulates the chronotropic responses of rabbit atria by acting on both H1- and H2-receptors. Cimetidine (H2-antagonist) and diphenhydramine (H1-antagonist) both cause some inhibition of the histamine response, but there is no evidence of competitive blockade with these antagonists given separately or in combination. 4-Methylhistamine (H2-agonist) stimulates chronotropic activity, and both H1- and H2-antagonists reduce this response to some degree. 2-Methylhistamine (H1-agonist) is a less effective agonist (perhaps rabbit atria contain fewer H1-receptors), but the response is also decreased by either H1-or H2-antagonists. These two "specific" agonists were combined to stimulate the histamine responses, and the antagonists were given simultaneously. The results were qualitatively similar to those obtained with histamine. The question remains: (1) are these agonists and antagonists specific or (2) are the rabbit atrial chronotropic receptors not typical of the H1- and H2-type receptor?

Authors

No affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

6129789

Citation

Hughes, M J.. "The Effects of Cimetidine On Histamine Atrial Chronotropic Receptor Activity." Agents and Actions, vol. 12, no. 4, 1982, pp. 425-30.
Hughes MJ. The effects of cimetidine on histamine atrial chronotropic receptor activity. Agents Actions. 1982;12(4):425-30.
Hughes, M. J. (1982). The effects of cimetidine on histamine atrial chronotropic receptor activity. Agents and Actions, 12(4), 425-30.
Hughes MJ. The Effects of Cimetidine On Histamine Atrial Chronotropic Receptor Activity. Agents Actions. 1982;12(4):425-30. PubMed PMID: 6129789.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The effects of cimetidine on histamine atrial chronotropic receptor activity. A1 - Hughes,M J, PY - 1982/10/1/pubmed PY - 1982/10/1/medline PY - 1982/10/1/entrez SP - 425 EP - 30 JF - Agents and actions JO - Agents Actions VL - 12 IS - 4 N2 - Clinically useful histamine antagonists have been reported to be specific for H1- or H2-receptors. However, data is accumulating that the specificity of those agents may be relative. This study was undertaken in an attempt to clarify this point. Histamine stimulates the chronotropic responses of rabbit atria by acting on both H1- and H2-receptors. Cimetidine (H2-antagonist) and diphenhydramine (H1-antagonist) both cause some inhibition of the histamine response, but there is no evidence of competitive blockade with these antagonists given separately or in combination. 4-Methylhistamine (H2-agonist) stimulates chronotropic activity, and both H1- and H2-antagonists reduce this response to some degree. 2-Methylhistamine (H1-agonist) is a less effective agonist (perhaps rabbit atria contain fewer H1-receptors), but the response is also decreased by either H1-or H2-antagonists. These two "specific" agonists were combined to stimulate the histamine responses, and the antagonists were given simultaneously. The results were qualitatively similar to those obtained with histamine. The question remains: (1) are these agonists and antagonists specific or (2) are the rabbit atrial chronotropic receptors not typical of the H1- and H2-type receptor? SN - 0065-4299 UR - https://www.unboundmedicine.com/medline/citation/6129789/The_effects_of_cimetidine_on_histamine_atrial_chronotropic_receptor_activity_ DB - PRIME DP - Unbound Medicine ER -