Inhibition of electrically evoked contractions of guinea-pig ileum preparations mediated by the histamine H3 receptor.
We investigated the contraction responses of isolated guinea-pig ileum preparations under several conditions of electrical field stimulation. Histamine H3-agonists caused a dose-dependent inhibition of both cholinergic and nonadrenergic noncholinergic (NANC) responses (pD2 of histamine, 7.3; N alpha-methylhistamine, 8.4; (R)-alpha-methylhistamine, 8.3); H3-antagonists blocked this inhibition (pA2 of impromidine, 7.2; thioperamide, 8.5). Our results indicate that H3-receptors are present on both cholinergic and NANC nerves in the myenteric plexus and that the preparation can be used as a rapid and simple test system for histamine H3-receptors.
Menkveld
G J
GJ
Department of Pharmacochemistry, Faculty of Chemistry, Vrije Universiteit, Amsterdam, The Netherlands.
Timmerman
H
H
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000187:drug effects; D004558:Electric Stimulation; D006146:Guanidines / Q000494:pharmacology; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology; D007082:Ileum / Q000187:drug effects; D007093:Imidazoles / Q000494:pharmacology; D017446:Impromidine; D066298:In Vitro Techniques; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D009197:Myenteric Plexus / Q000187:drug effects; D010275:Parasympathetic Nervous System / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology; D011968:Receptors, Histamine / Q000502:physiology*; D018100:Receptors, Histamine H3; D013779:Tetrodotoxin / Q000494:pharmacology
D006146:Guanidines; D007093:Imidazoles; D008761:Methylhistamines; D010880:Piperidines; D011968:Receptors, Histamine; D018100:Receptors, Histamine H3; D013779:Tetrodotoxin; D001285:Atropine; D006632:Histamine; D017446:Impromidine; C052075:thioperamide; C048140:N-methylhistamine