Functional dopamine D2 receptors on rat vagal afferent neurones

Abstract

1 In the present study in vitro electrophysiology and receptor autoradiography were used to determine whether rat vagal afferent neurones possess dopamine D2 receptors. 2 Dopamine (10–300 μm) elicited a temperature‐ and concentration‐dependent depolarization of the rat isolated nodose ganglion preparation. When applied to the tissue 15 min prior to agonist, raclopride (10 μm), clozapine (10 μm) or a mixture of raclopride and clozapine (10 μm each) all produced a threefold parallel shift to the right of the dopamine concentration‐response curve. In contrast, SCH 23390 (100 nM), phentolamine and propranolol (1 μm each) failed to antagonize the dopamine‐mediated depolarization. 3 [125I]‐NCQ 298..