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: 71/3/909    most recent biolreprod.104.030072v1 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 PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Greenwood, A. K. Articles by Fernald, R. D. Search for Related Content PubMed PubMed Citation Articles by Greenwood, A. K. Articles by Fernald, R. D. Agricola Articles by Greenwood, A. K. Articles by Fernald, R. D.

Social Regulation of the Electrical Properties of Gonadotropin-Releasing Hormone Neurons in a Cichlid Fish (Astatotilapia burtoni)¹

Program in Neuroscience, Stanford University, Stanford, California 94305

Variation in reproductive capacity is common across the lives of all animals. In vertebrates, hypothalamic neurons that secrete GnRH are a primary mediator of such reproductive plasticity. Since social interactions suppress gonadal maturity in the African cichlid fish, Astatotilapia (Haplochromis) burtoni, we investigated whether the electrical properties of GnRH neurons were also socially regulated. Adult A. burtoni males are either territorial (T) and reproductively active or nonterritorial (NT) and reproductively regressed, depending upon their social environment. We compared the basic electrical properties of hypothalamic GnRH neurons from T and NT males using whole-cell electrophysiology in vitro. GnRH neurons were spontaneously active and exhibited several different activity patterns. A small fraction of neurons exhibited episodic activity patterns, which have been described in GnRH neurons from mammals. The type of activity pattern and spontaneous firing rate did not vary with reproductive capacity; however, several basic electrical properties were different. Neurons from T males were larger than those from NT males and had higher membrane capacitance and lower input resistance. In neurons from NT males, action potential duration was significantly longer and after-hyperpolarization characteristics were diminished, which led to a tendency for neurons from NT males to fire less rapidly in response to current injection. We predict this could serve to decrease GnRH release in NT males. These data are the first electrophysiological characterization of hypothalamic GnRH neurons in a nonmammalian species and provide evidence for several changes in electrical properties with reproductive state.

¹ Supported by a NINDS 34950/Javits award to R.D.F.

² Correspondence: Anna K. Greenwood, Jordan Hall, Building 420, Stanford University, Stanford, CA 94305-2130. FAX: 650 723 0881; akg{at}stanfordalumni.org

This article has been cited by other articles:

				S. C. P. Renn, N. Aubin-Horth, and H. A. Hofmann Fish and chips: functional genomics of social plasticity in an African cichlid fish J. Exp. Biol., September 15, 2008; 211(18): 3041 - 3056. [Abstract] [Full Text] [PDF]

				M. M. Holmes, G. J. Rosen, C. L. Jordan, G. J. de Vries, B. D. Goldman, and N. G. Forger Social control of brain morphology in a eusocial mammal PNAS, June 19, 2007; 104(25): 10548 - 10552. [Abstract] [Full Text] [PDF]

				N. L. Wayne, K. Kuwahara, K. Aida, Y. Nagahama, and K. Okubo Whole-Cell Electrophysiology of Gonadotropin-Releasing Hormone Neurons that Express Green Fluorescent Protein in the Terminal Nerve of Transgenic Medaka (Oryzias latipes) Biol Reprod, December 1, 2005; 73(6): 1228 - 1234. [Abstract] [Full Text] [PDF]