Journal article

INHIBITION OF 5-CARBOXAMIDOTRYPTAMINE-INDUCED RELAXATION OF GUINEA-PIG ILEUM CORRELATES WITH [I-125] LSD BINDING

HO KALKMAN, G ENGEL, D HOYER

EUROPEAN JOURNAL OF PHARMACOLOGY | ELSEVIER SCIENCE BV | Published : 1986

Abstract

5-Hydroxytryptamine (5-HT), 5-carboxamidotryptamine (5-CT), 8-OH-DPAT and RU 24969 relax the guinea-pig ileum precontracted with histamine. This relaxation was characterized using 5-CT as agonist with a series of 8 competitive antagonists. [125I]LSD binding was measured in a membrane preparation of the longitudinal muscle of the guinea-pig ileum in the presence of 3 X 10(-7) M cinanserin in order to suppress binding to 5-HT2 receptors. There was a significant correlation (P less than 0.01) between the antagonism of 5-CT-induced relaxation (pA2 values) and the affinity values of the antagonists for [125I]LSD binding (pKD values). It was also shown that 5-CT relaxed histamine-precontracted lon..

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