Behavioral effects of neuropeptide E-I (NEI) in the female rat: interactions with alpha-MSH, MCH and dopamine.

The behavioral and neurochemical effects of NEI, and its interaction with alpha-MSH or MCH were investigated in the ventromedial nucleus (VMN) and medial preoptic area (MPOA) in female rats (bilateral administration, 100 ng in 0.5 microliter/side). NEI in the VMN (but not in the MPOA) stimulated exploratory behavior, increased anxiety and reduced dopamine and DOPAC release. The behavioral effects were antagonized by alpha-MSH. NEI stimulated female sexual receptivity in the MPOA. In the VMN, NEI did not have any effect on sexual activity, but partially antagonized the stimulatory effect of MCH. These results show that NEI in the hypothalamus participates in the regulation of behavior, possibly through dopaminergic mediation.