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Histamine receptors in the myenteric plexus-longitudinal muscle of the guinea-pig ileum: H1- and H2-receptor-mediated potentiation of the contractile response to electrical stimulation.
J Pharmacol Exp Ther. 1982 Oct; 223(1):177-82.JP

Abstract

The effect of histamine on the contractile response to low frequency-electrical field stimulation in the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum was investigated. By blocking the direct increase in smooth muscle tone caused by histamine with low concentrations of pyrilamine (10(-9)--5 x 10(-8) M) a dose-dependent, histamine-induced potentiation of the twitch response to electrical stimulation was observed. Blocking the direct actions of histamine with concentrations of pyrilamine greater than 10(-7) M resulted in a biphasic histamine dose-response curve: lower histamine concentrations produced a dose-dependent decrease of the twitch response; higher concentrations produced a potentiation. The potentiating effect of histamine was inhibited by high concentrations of H2-receptor antagonists. Tiotidine (ICI 125, 211) had a pA2 of 5.25, 100 times greater than its pA2 in isolated guinea-pig atria. Blockade of the actions of the H2-receptor agonists dimaprit and tetrahydrozoline also required greater antagonist concentrations. The selective H1-receptor agonist, 2-(2-thiazolyl)-ethylamine, also enhanced the response to electrical stimulation. The potentiating effect of histamine could be blocked by hexamethonium (10(-7)--10(-5) M) but not by atropine. Atropine (10(-9)--10(-8) M) did prevent the decrease in the contraction amplitude induced by histamine in the presence of 10(-7) M pyrilamine. The purinergic antagonist theophylline, adrenergic antagonists or depletion of endogenous catecholamines were without effect. Tetrodotoxin (10(-6) M) inhibited the augmentation induced by histamine. Our results demonstrate that histamine potentiates the acetylcholine-mediated contractile response to electrical field stimulation of guniea-pig ileum via H1- and what may be an H2-receptor subtype.

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

6126581

Citation

Zavecz, J H., and T O. Yellin. "Histamine Receptors in the Myenteric Plexus-longitudinal Muscle of the Guinea-pig Ileum: H1- and H2-receptor-mediated Potentiation of the Contractile Response to Electrical Stimulation." The Journal of Pharmacology and Experimental Therapeutics, vol. 223, no. 1, 1982, pp. 177-82.
Zavecz JH, Yellin TO. Histamine receptors in the myenteric plexus-longitudinal muscle of the guinea-pig ileum: H1- and H2-receptor-mediated potentiation of the contractile response to electrical stimulation. J Pharmacol Exp Ther. 1982;223(1):177-82.
Zavecz, J. H., & Yellin, T. O. (1982). Histamine receptors in the myenteric plexus-longitudinal muscle of the guinea-pig ileum: H1- and H2-receptor-mediated potentiation of the contractile response to electrical stimulation. The Journal of Pharmacology and Experimental Therapeutics, 223(1), 177-82.
Zavecz JH, Yellin TO. Histamine Receptors in the Myenteric Plexus-longitudinal Muscle of the Guinea-pig Ileum: H1- and H2-receptor-mediated Potentiation of the Contractile Response to Electrical Stimulation. J Pharmacol Exp Ther. 1982;223(1):177-82. PubMed PMID: 6126581.
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TY - JOUR T1 - Histamine receptors in the myenteric plexus-longitudinal muscle of the guinea-pig ileum: H1- and H2-receptor-mediated potentiation of the contractile response to electrical stimulation. AU - Zavecz,J H, AU - Yellin,T O, PY - 1982/10/1/pubmed PY - 1982/10/1/medline PY - 1982/10/1/entrez SP - 177 EP - 82 JF - The Journal of pharmacology and experimental therapeutics JO - J. Pharmacol. Exp. Ther. VL - 223 IS - 1 N2 - The effect of histamine on the contractile response to low frequency-electrical field stimulation in the myenteric plexus-longitudinal muscle preparation of the guinea-pig ileum was investigated. By blocking the direct increase in smooth muscle tone caused by histamine with low concentrations of pyrilamine (10(-9)--5 x 10(-8) M) a dose-dependent, histamine-induced potentiation of the twitch response to electrical stimulation was observed. Blocking the direct actions of histamine with concentrations of pyrilamine greater than 10(-7) M resulted in a biphasic histamine dose-response curve: lower histamine concentrations produced a dose-dependent decrease of the twitch response; higher concentrations produced a potentiation. The potentiating effect of histamine was inhibited by high concentrations of H2-receptor antagonists. Tiotidine (ICI 125, 211) had a pA2 of 5.25, 100 times greater than its pA2 in isolated guinea-pig atria. Blockade of the actions of the H2-receptor agonists dimaprit and tetrahydrozoline also required greater antagonist concentrations. The selective H1-receptor agonist, 2-(2-thiazolyl)-ethylamine, also enhanced the response to electrical stimulation. The potentiating effect of histamine could be blocked by hexamethonium (10(-7)--10(-5) M) but not by atropine. Atropine (10(-9)--10(-8) M) did prevent the decrease in the contraction amplitude induced by histamine in the presence of 10(-7) M pyrilamine. The purinergic antagonist theophylline, adrenergic antagonists or depletion of endogenous catecholamines were without effect. Tetrodotoxin (10(-6) M) inhibited the augmentation induced by histamine. Our results demonstrate that histamine potentiates the acetylcholine-mediated contractile response to electrical field stimulation of guniea-pig ileum via H1- and what may be an H2-receptor subtype. SN - 0022-3565 UR - https://www.unboundmedicine.com/medline/citation/6126581/Histamine_receptors_in_the_myenteric_plexus_longitudinal_muscle_of_the_guinea_pig_ileum:_H1__and_H2_receptor_mediated_potentiation_of_the_contractile_response_to_electrical_stimulation_ L2 - http://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=6126581 DB - PRIME DP - Unbound Medicine ER -