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Updated: Aug 2, 2026
10:56
Long-term Behavioral Tracking of Freely Swimming Weakly Electric Fish
Published on: March 6, 2014
Cyclic AMP modulates electrical signaling in a weakly electric fish
L McAnelly1, A Silva, H H Zakon
1Section of Neurobiology, Patterson Laboratory, The University of Texas at Austin, 1 University Station C0920, Austin, TX 78712, USA. l.mcanelly@mail.utexas.edu
Summary
Protein kinase A activation in electric fish (Sternopygus macrurus) increases electric organ discharge amplitude by altering electrocyte biophysical properties, not just action potential size.
Area of Science:
- Neuroscience
- Electrophysiology
- Animal Behavior
Background:
- Electric fish exhibit variable electric organ discharge (EOD) amplitude influenced by time of day and social cues.
- Protein kinase A (PKA) activation by 8-bromo-cAMP enhances sodium current in electrocytes of Sternopygus macrurus.
Purpose of the Study:
- To investigate if behavioral plasticity in EOD amplitude is regulated by electrocyte biophysical properties.
- To determine if PKA-mediated phosphorylation effects on ion currents directly impact EOD changes.
Main Methods:
- Injection of 8-bromo-cAMP into the electric organ of restrained Sternopygus macrurus.
- Monitoring of EOD amplitude and pulse duration.
- Two-electrode current clamp to examine PKA activation effects on electrocyte action potentials in isolated electric organs.
Main Results:
- 8-bromo-cAMP significantly increased EOD amplitude (approx. 400%) and pulse duration (approx. 25%).
- Action potential amplitude increased by approx. 40%, with duration also increasing by approx. 25%.
- Resting membrane resistance in electrocytes decreased following 8-bromo-cAMP exposure.
Conclusions:
- A moderate increase in action potential amplitude coupled with decreased electrocyte membrane resistance amplifies the voltage drop across external resistance.
- This mechanism explains the substantial increase in externally recorded EOD amplitude, linking cellular biophysics to behavioral plasticity in electric fish.
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