TY - JOUR T1 - Pharmacological characterization of 5-hydroxytryptamine4(5-HT4) receptors positively coupled to adenylate cyclase in adult guinea pig hippocampal membranes: effect of substituted benzamide derivatives. JF - Molecular Pharmacology JO - Mol Pharmacol SP - 408 LP - 411 VL - 37 IS - 3 AU - J Bockaert AU - M Sebben AU - A Dumuis Y1 - 1990/03/01 UR - http://molpharm.aspetjournals.org/content/37/3/408.abstract N2 - Adult guinea pig hippocampal membranes contain two 5-hydroxytryptamine (5-HT) receptors positively coupled with an adenylate cyclase. One is a typical 5-HT1A receptor and the second is a nonclassical 5-HT receptor that we previously proposed to call 5-HT4. Here, we show that 4-amino-5-chlor-2-methoxy-benzamide derivatives are agonists of 5-HT4 receptors in guinea pig hippocampal membranes. Their effects on the adenylate cyclase of these membranes are not additive with those of 5-HT but are additive with those of RU 24969, a typical 5-HT1 agonist. The effects of benzamides, as well as those of 5-HT, on 5-HT4 receptors are not blocked by 5-HT1, 5-HT2, or 5-HT3 antagonists except ICS 205 903, which does so with a low affinity (1 microM). The potency of benzamides (cisapride greater than BRL 24924 greater than zacopride greater than BRL 20627 greater than metoclopramide) is similar to their effect of 5-HT4 receptors positively coupled with an adenylate cyclase of fetal mouse colliculi neurons. ER -