Acetylcholine mediation of the contractile response to histamine in human bladder detrusor muscle.
In Krebs solution, histamine evokes in human bladder detrusor muscle strips a dose-dependent contractile response which consists of two pharmacologically distinct responses: a high-sensitivity response evoked at 0.4-2 microM histamine, which is potentiated by neostigmine (0.1 microM) or blocked by atropine (0.1 microM) or ranitidine (1 microM); a low-sensitivity response evoked at 4-40 microM histamine and blocked by dimethindene or diphenhydramine. These findings suggest that the contractile response to low doses of histamine is mediated by acetylcholine released from a site proximal to the muscle. This effect of histamine seems to be mediated by a site which is insensitive to the H1 antagonists dimethindene and diphenhydramine but blocked by the H2 antagonist ranitidine.
Department of Physiology and Pharmacology, Tel Aviv University Sackler School of Medicine, Israel.
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R
Rubinstein
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I
Nissenkorn
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S
Cohen
D000109:Acetylcholine / Q000502:physiology*; D001285:Atropine / Q000494:pharmacology; D004115:Dimethindene / Q000494:pharmacology; D004155:Diphenhydramine / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000187:drug effects*; D009388:Neostigmine / Q000494:pharmacology; D011899:Ranitidine / Q000494:pharmacology; D001743:Urinary Bladder / Q000187:drug effects
D009388:Neostigmine; D004115:Dimethindene; D001285:Atropine; D006632:Histamine; D011899:Ranitidine; D004155:Diphenhydramine; D000109:Acetylcholine