HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 102/2/752    most recent 90469.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Yu, H. J. Articles by Yamaguchi, A. PubMed PubMed Citation Articles by Yu, H. J. Articles by Yamaguchi, A.

5-HT_2C-Like Receptors in the Brain of Xenopus laevis Initiate Sex-Typical Fictive Vocalizations

Department of Biology, Boston University, Boston, Massachusetts

Submitted 14 April 2008; accepted in final form 22 May 2009

Vocalizations of male and female African clawed frogs (Xenopus laevis) are generated by brain stem central pattern generators. Serotonin (5-HT) is likely important for vocal initiation because, when applied in vitro, sex-typical fictive vocalizations are evoked from isolated brains. To explore the mechanisms underlying vocal initiation, we identified the types of serotonin receptors mediating vocal activation pharmacologically using a whole brain, fictive preparation. The results showed that 5-HT_2C–like receptors are important for activation of fictive vocalizations in the sexes. 5-HT_2C receptor agonists elicited fictive vocalizations, and 5-HT_2C receptor antagonists blocked 5-HT–induced fictive vocalizations, whereas agonists and antagonists of 5-HT_2A and 5-HT_2B receptors failed to initiate or block 5-HT–induced fictive vocalizations in the sexes. The results indicate that serotonin initiates fictive vocalizations by binding to 5-HT_2C–like receptors located either within or upstream of the vocal central pattern generator in both sexes. We conclude that the basic mechanism of vocal initiation is shared by the sexes despite the differences in the actual vocalizations between males and females. Sex-typical vocalizations, therefore, most likely arise from activation of different populations of 5-HT_2C receptor expressing cells or from differential activation of downstream pattern generating neurons.