title: Histamine receptors in primate gallbladder.
abstract: The effect of intravenous histamine on intragallbladder pressure (GBp) and subsequent modification of the histamine response by H1- and H2-antagonists was investigated in an awake baboon model. Responses to specific H1- and H2-agonists were also examined in order to further elucidate gallbladder histamine responses. Gallbladder volume (GBv) was arbitrarily set at 60-70% of observed resting GBv, and drugs were then infused intravenously with continuous monitoring of GBp. Histamine administration resulted in a logarithmic dose--response curve with a maximal increase in GBp equal to 31.7 mm Hg at a dose of 0.0625 mg of histamine. Infusion of the H1-antagonist diphenhydramine hydrochloride (Benadryl) resulted in a decreased GBp response to histamine when compared to preblocker response at all doses studied. On the other hand, histamine response following administration of the H2-antagonist metiamide was significantly greater than the preblocker histamine response. Infusion of the H1-agonist 2-pyridylethlamine resulted in a dose-dependent increase in GBp similar to the histamine curve, while infusion of the H2-agonist dimaprit resulted in consistent decreases in GBp. These results extend previous observations in subprimate preparations and demonstrate the presence of both stimulatory H1-receptors and inhibitory H2-receptors in an in situ primate model.
mesh_terms: D000818:Animals; D017259:Dimaprit; D004305:Dose-Response Relationship, Drug; D005260:Female; D005704:Gallbladder / Q000187:drug effects*; D006632:Histamine / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D010215:Papio; D011312:Pressure; D011725:Pyridines / Q000494:pharmacology; D011968:Receptors, Histamine / Q000502:physiology*; D011969:Receptors, Histamine H1 / Q000187:drug effects / Q000502:physiology*; D011970:Receptors, Histamine H2 / Q000187:drug effects / Q000502:physiology*; D013890:Thiourea / Q000494:pharmacology
chemical_list: D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D011725:Pyridines; D011968:Receptors, Histamine; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D006632:Histamine; C006183:2-(2-aminoethyl)pyridine; D013890:Thiourea; D017259:Dimaprit