Neuroscience 2005 Abstract
| Presentation Number: | 205.1 |
|---|---|
| Abstract Title: | ACTH modulates electrocommunication via effects on the electrocyte sodium current. |
| Authors: |
McAnelly, M.*1
; Markham, M.2
1Sect. Neurobiol., Univ. of Texas , Austin, TX 2FL, 1 University Station C0920, 78712, |
| Primary Theme and Topics |
Cognition and Behavior - Neuroethology -- Regulatory factors (hormones, neuropeptides, and cytokines) |
| Session: |
205. Neuroethology Poster |
| Presentation Time: | Sunday, November 13, 2005 8:00 AM-9:00 AM |
| Location: | Washington Convention Center - Hall A-C, Board # QQ12 |
| Keywords: | ELECTRIC FISH, STERNOPYGUS, PROTEIN KINASE A, ION CHANNEL |
Electric fish generate an electric organ discharge (EOD) by which they convey information about gender and individual identity, reproductive condition, and social dominance. In some species, the amplitude of the EOD increases during the dark phase of the photoperiod when fish are socially active, and in response to the presence of another male. Such increases in EOD amplitude can be mimicked by systemic injection with the peptide adrenocorticotropic hormone (ACTH) (Markham, Haskell-Luevano & Stoddard, SFN 2004). ACTH also increases the amplitude of the extracellularly recorded potential when directly applied to an isolated electric organ, demonstrating that ACTH exerts its effects locally on the electric organ. ACTH binds to melanocortin receptors (MCRs) and activates the adenylyl cyclase/PKA signaling pathway. This suggests that ACTH increases EOD amplitude via activation of PKA. Indeed, treatment of isolated electric organ cells with 8bromo cAMP (8Br cAMP) increases the magnitude of the Na+ current under voltage clamp (McAnelly & Zakon, 1996). However, it has not yet been demonstrated that ACTH influences the Na+ current. We therefore applied ACTH to isolated electric organ tissue while voltage clamping the cells. ACTH increased INa by 17% after 30 minutes of exposure, while INa decreased by 25% in normal saline. This is a relative increase of 42% which is significantly different at p = .0003. PKA blockers will be used to ascertain whether this effect of ACTH is mediated by PKA.
Supported by NIH R01 NS025513, NIMH 1K01MH064550 and NIH S06-GM08205
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2005 Neuroscience Meeting Planner. Washington, DC: Society for Neuroscience, 2005. Online.
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