Androgens alter electric organ discharge pulse duration despite stability in electric organ discharge frequency

Authors
Citation
Wp. Few et Hh. Zakon, Androgens alter electric organ discharge pulse duration despite stability in electric organ discharge frequency, HORMONE BEH, 40(3), 2001, pp. 434-442
Citations number
52
Categorie Soggetti
Neurosciences & Behavoir
Journal title
HORMONES AND BEHAVIOR
ISSN journal
0018506X → ACNP
Volume
40
Issue
3
Year of publication
2001
Pages
434 - 442
Database
ISI
SICI code
0018-506X(200111)40:3<434:AAEODP>2.0.ZU;2-F
Abstract
Weakly electric fish in the genus Sternopygus emit a sinusoidal, individual ly distinct, and sexually dimorphic electric organ discharge (EOD) that is used in electrolocation and communication. Systemically applied androgens d ecrease EOD frequency, which is set by a medullary pacemaker nucleus, and i ncrease pulse duration, which is determined by the cells of the electric or gan (the electrocytes), in a coordinated fashion. One possibility is that a ndrogens broaden the EOD pulse duration by acting on the pacemaker neurons, thereby effecting a change in pacemaker firing frequency, and that the cha nge in EOD pulse duration is due to an activity-dependent process. To deter mine whether androgens can alter pulse duration despite a stable pacemaker nucleus firing frequency, we implanted small doses of dihydrotestosterone i n the electric organ. We found that androgen implants increased EOD pulse d uration, but did not influence EOD frequency. In addition, using immunocyto chemistry, we found that electrocytes label positively with an androgen rec eptor antibody. While it is not known on which cells androgens act directly , together these experiments suggest that they likely act on the electrocyt es to increase EOD pulse duration. Since pulse duration is determined by el ectrocyte action potential duration and ionic current kinetics, androgens m ay therefore play a causative role in influencing individual variation and sexual dimorphism in electrocyte electrical excitability, an important comp onent of electrocommunicatory behavior. (C) 2001 Academic Press.