Galanin antagonizes vasopressin-stimulated flank marking in male golden hamsters

Microinjection of vasopressin (VP) into the anterior hypothalamus (AH) of g olden hamsters induces a rapid bout of flank marking, a stereotyped scent m arking behavior used for olfactory communication. In rats, VP is colocalize d with galanin (GAL) in several brain regions. GAL has been shown to antago nize the postsynaptic actions of other cosecreted neurotransmitters includi ng acetylcholine and norepinephrine; however, the ability of GAL to modulat e the postsynaptic actions of VP has not been assessed. Here, we report tha t coadministration of GAL can block VP-induced flank marking in golden hams ters in a dose dependent manner. These findings provide the first evidence in any species that GAL can antagonize the central actions of VP. Using sli ce binding and receptor autoradiography, we have identified GAL binding sit es in the AH and two other regions implicated in flank marking behavior (th e lateral septum and central grey). These findings raise the possibility th at endogenous GAL may function as an inhibitory modulator of this stereotyp ic scent marking behavior. (C) 1999 Published by Elsevier Science B.V. All rights reserved.