In communication systems it is important for the signal and receiver to be matched in the frequency domain to maximize information transfer. Thus, the frequency sensitivity of a species' sensory systems are often matched to the spectrum of that species' communication signal. Nevertheless, little is known about the developmental mechanisms by which output and sensory structures come to be matched or whether they have any capacity for plasticity in mature animals. The match between signal and receiver are extremely precise in those animals that have """"""""active"""""""" sensory systems like echolocating bats and electrolocating weakly electric fish. Weakly electric fish are intriguing because the frequency sensitivity of the sensory receptors and the frequency output of the emitter, the electric organ, are not only well matched but both effector and receptor pathways show hormone-mediated plasticity. of prime interest is how the ion currents of the cells in this communication pathway are modulated by hormones. In this proposal we concentrate on hormone induced plasticity of the emitter, the electric organ, where our preliminary data suggest that, variation in and plasticity of a Na+ current is the major determinant of the waveshape properties of its output and the locus of hormone-mediated plasticity. In this proposal we wish to 1) measure additional properties of the Na+ currents (i.e.--I-V curves, steady state inactivation, recovery from inactivation, dissociation constants for TTX and mu conotoxin) to determine if other parameters also vary with electrocyte (a single electric organ cell) spike duration 2) determine whether the kinetics of the delayed rectifying K+ current in electrocytes from fish with a range of EOD frequencies also show individual variation 3) record Na+ currents and K+ currents before and after fish have been treated with androgens or gonadotropin to determine whether the kinetics of these currents can be altered by these hormones 4) determine whether Na+ current kinetics are altered by treatment of the electrocytes with agents that induce phosphorylation of the Na+ channel in other preparations.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS025513-09
Application #
2858118
Study Section
Special Emphasis Panel (ZRG1-CMS (01))
Program Officer
Kitt, Cheryl A
Project Start
1989-08-01
Project End
2000-12-31
Budget Start
1999-01-01
Budget End
2000-12-31
Support Year
9
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Texas Austin
Department
Zoology
Type
Schools of Arts and Sciences
DUNS #
City
Austin
State
TX
Country
United States
Zip Code
78712
Zakon, Harold H (2012) Adaptive evolution of voltage-gated sodium channels: the first 800 million years. Proc Natl Acad Sci U S A 109 Suppl 1:10619-25
Markham, Michael R; McAnelly, M Lynne; Stoddard, Philip K et al. (2009) Circadian and social cues regulate ion channel trafficking. PLoS Biol 7:e1000203
Liu, He; Wu, Ming-ming; Zakon, Harold H (2008) A novel Na+ channel splice form contributes to the regulation of an androgen-dependent social signal. J Neurosci 28:9173-82
McAnelly, M Lynne; Zakon, Harold H (2007) Androgen modulates the kinetics of the delayed rectifying K+ current in the electric organ of a weakly electric fish. Dev Neurobiol 67:1589-97
Liu, He; Wu, Ming-Ming; Zakon, Harold H (2007) Individual variation and hormonal modulation of a sodium channel beta subunit in the electric organ correlate with variation in a social signal. Dev Neurobiol 67:1289-304
Few, W Preston; Zakon, Harold H (2007) Sex differences in and hormonal regulation of Kv1 potassium channel gene expression in the electric organ: molecular control of a social signal. Dev Neurobiol 67:535-49
Stoddard, Philip K; Zakon, Harold H; Markham, Michael R et al. (2006) Regulation and modulation of electric waveforms in gymnotiform electric fish. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 192:613-24
Zakon, Harold H; Lu, Ying; Zwickl, Derrick J et al. (2006) Sodium channel genes and the evolution of diversity in communication signals of electric fishes: convergent molecular evolution. Proc Natl Acad Sci U S A 103:3675-80
Novak, Alicia E; Jost, Manda C; Lu, Ying et al. (2006) Gene duplications and evolution of vertebrate voltage-gated sodium channels. J Mol Evol 63:208-21
Bass, Andrew H; Zakon, Harold H (2005) Sonic and electric fish: at the crossroads of neuroethology and behavioral neuroendocrinology. Horm Behav 48:360-72

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