[Spinal ganglion neurons of rats--a model for the study of the central serotonin receptors].

Application of 5-hydroxytryptamine (5-HT) (3 x 10(-5) M) on the rat lumbar dorsal ganglia (RDG) induced membrane depolarization with increased input resistance in 30% of neurons, hyperpolarization with decreased input resistance in 30% of neurons and mixed responses in 40% of neurons. Methysergide and amitriptyline (10(-6) M) blocked depolarizing but not hyperpolarizing effects of 5-HT. Propranolol (3 x 10(-6) M) was inactive in respect to both 5-HT responses. 5-HT depolarizing responses of RDG neurons were mediated by 5-HT2 receptors activation and decreased membrane potassium conductivity; 5-HT hyperpolarizing responses were mediated by 5-HT1A receptor activation and increased potassium conductivity. RDG neurons seem to be an interesting model for the investigation of central 5-HT receptor mechanism.