Blockade of histamine-induced contractions of guinea pig ielum by beta-haloalkylamines.
In the longitudinal muscle strip of guinea pig ileum phenoxybenzamine (POB) produces a maximum parallel shift of 0.7 log units in the dose-response curve to histamine. In the presence of sodium thiosulfate in the wash fluid the parallel shift whith retention of maximum response increases to about 2 log units, and a similar value is obtained for Nethyl-N-(2-bromoethyl)-1-naphthylamine. The The agent N-ethyl-N- (2-chloroethyl)benzylamine produces a significantly smaller shift of dose-response curve of 1.53 log units before the maximum response becomes depressed. The receptor-specific depression of maximum response produced by higher doses of POB is reversed by sodium thiosulfate and by bovine serum albumin, while the parallel shift in dose-response curve is unaffected by both treatments. These findings may be explained by a hypothesis involving interaction of 2-haloalkylamines at two sites.
D000588:Amines / Q000494:pharmacology*; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D003864:Depression, Chemical; D006168:Guinea Pigs; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D007082:Ileum / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D010643:Phenoxybenzamine / Q000494:pharmacology; D011955:Receptors, Drug / Q000187:drug effects; D013997:Time Factors
D000588:Amines; D001596:Benzylamines; D006634:Histamine H1 Antagonists; D011955:Receptors, Drug; D010643:Phenoxybenzamine