An intracellular study of the action of NAN-190 on neurons in the dorsal raphe nucleus of the rat.

Intracellular recordings have been made from neurons in the dorsal raphe (DR) nucleus of the rat to determine the mechanism of action of the arylpiperazine compound NAN-190. Application of NAN-190 (50 microM) alone most frequently caused a hyperpolarization accompanied by a fall in RM and reduced the response to 5-HT and 8-OH-DPAT. After pretreatment of the preparation with the 5-HT-uptake blocker citalopram (10 microM) NAN-190 exerted an excitatory effect. It is concluded that NAN-190 is a partial agonist in the DR nucleus.