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5‐HT 3 receptors do not mediate vagally‐induced relaxation or contraction of the isolated stomach of the guinea‐pig
Author(s) -
Desai Kaushik M.,
Warner Timothy D.,
Vane John R.
Publication year - 1994
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1994.tb14066.x
Subject(s) - contraction (grammar) , metoclopramide , endocrinology , medicine , methysergide , 5 ht receptor , receptor , ondansetron , guinea pig , chemistry , serotonin , stimulation , vagus nerve , muscle contraction , vomiting
1 We have tested whether 5‐HT 3 receptors mediate vagally‐induced relaxation or contraction of the isolated stomach of the guinea‐pig. 2 The antagonists of 5‐HT 3 receptors, ondansetron (1–10 μ m ) or metoclopramide (1–30 μ m ) did not inhibit vagally‐induced relaxations at low concentrations but partially inhibited them at 30 μ m or 60 μ m , respectively. These higher concentrations of ondansetron and metoclopramide also inhibited relaxations induced by 1,1‐dimethyl‐4‐phenylpiperazinium iodide (30 μ m ) but did not affect those induced by glyceryl trinitrate (0.7–1.1 μ m ). 3 Desensitization to 5‐HT (100 μ m ) or 2‐Me‐5‐HT (100 μ m ) did not affect relaxations or contractions induced by vagal stimulation. 4 Ondansetron (30 μ m ) or metoclopramide (60 μ m ) did not inhibit vagally‐induced gastric contraction. 5 Thus, 5‐HT 3 receptors do not mediate vagally‐induced relaxation or contraction in the guinea‐pig stomach.