Serotonergic modulation of startle-escape plasticity in an African cichlid fish: a single-cell molecular and physiological analysis of a vital neural circuit
| Autor: | Hans A. Hofmann, Celeste E. Kidd, Heike Neumeister, Keith W. Whitaker, Lin S. Huffman, Thomas G. Preuss |
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| Rok vydání: | 2011 |
| Předmět: |
Male
Reflex Startle Serotonin Astatotilapia burtoni Physiology Cell Serotonergic Mauthner cell Neurochemical Cichlid Escape Reaction medicine Biological neural network Animals Neuronal Plasticity biology General Neuroscience Cichlids biology.organism_classification Electrophysiological Phenomena medicine.anatomical_structure Social Dominance Receptors Serotonin Fish Female Receptors Serotonin 5-HT2 Neuroscience |
| Zdroj: | Journal of neurophysiology. 106(1) |
| ISSN: | 1522-1598 |
| Popis: | Social life affects brain function at all levels, including gene expression, neurochemical balance, and neural circuits. We have previously shown that in the cichlid fish Astatotilapia burtoni brightly colored, socially dominant (DOM) males face a trade-off between reproductive opportunities and increased predation risk. Compared with camouflaged subordinate (SUB) males, DOMs exposed to a loud sound pip display higher startle responsiveness and increased excitability of the Mauthner cell (M-cell) circuit that governs this behavior. Using behavioral tests, intracellular recordings, and single-cell molecular analysis, we show here that serotonin (5-HT) modulates this socially regulated plasticity via the 5-HT receptor subtype 2 (5-HTR2). Specifically, SUBs display increased sensitivity to pharmacological manipulation of 5-HTR2 compared with DOMs in both startle-escape behavior and electrophysiological properties of the M-cell. Immunohistochemistry showed serotonergic varicosities around the M-cells, further suggesting that 5-HT impinges directly onto the startle-escape circuitry. To determine whether the effects of 5-HTR2 are pre- or postsynaptic, and whether other 5-HTR subtypes are involved, we harvested the mRNA from single M-cells via cytoplasmic aspiration and found that 5-HTR subtypes 5A and 6 are expressed in the M-cell. 5-HTR2, however, was absent, suggesting that it affects M-cell excitability through a presynaptic mechanism. These results are consistent with a role for 5-HT in modulating startle plasticity and increase our understanding of the neural and molecular basis of a trade-off between reproduction and predation. |
| Databáze: | OpenAIRE |
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