Melatonin inhibits Arg-vasopressin release via MT2 receptor in the suprachiasmatic nucleus-slice culture of rats

The effect of melatonin on the release of Arg-vasopressin (AVP) was analyze d in a suprachiasmatic nucleus-slice explant culture. The release of AVP in to the culture medium exhibited a circadian rhythm, with higher level durin g the subjective day and lower level during the subjective night. Melatonin (500 nM) inhibited the release of AVP. Luzindole, a MT2 (Mel 1b) melatonin receptor antagonist, attenuated the effect of melatonin on the AVP release . Results indicate that the inhibition of AVP release by melatonin in the s uprachiasmatic nucleus-slice culture depends at least in part on the melato nin MT, receptor. (C) 2001 Elsevier Science B.V. All rights reserved.