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Skin darkening, a potential social signal in subordinate arctic charr (Salvelinus alpinus): the regulatory role of brain monoamines and pro-opiomelanocortin-derived peptides.
- Source :
-
The Journal of experimental biology [J Exp Biol] 2000 Jun; Vol. 203 (Pt 11), pp. 1711-21. - Publication Year :
- 2000
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Abstract
- Arctic charr were allowed to interact in groups of three for 5 days. Skin darkness was quantified by measuring the mean brightness of individual fish before and after social interaction. Brain levels of monoamines and monoamine metabolites and plasma concentrations of cortisol, adrenocorticotropic hormone (ACTH), N-acetyl-(beta)-endorphin and alpha-melanocyte-stimulating hormone (alpha-MSH) were analysed. The results show that social subordination resulted in a significant skin darkening. Furthermore, plasma concentrations of alpha-MSH, ACTH and cortisol were elevated in subordinates, and these fish also displayed elevated levels of 5-hydroxyindoleacetic acid (5-HIAA) in the telencephalon. The ratio of [5-HIAA] to serotonin [5-HT] was increased in several brain areas. In addition, the ratio of 3-methoxy-4-hydroxyphenylglycol (MHPG) to norepinephrine (NE) concentrations was significantly increased in the optic tectum of subordinate fish. Skin darkness following social interaction showed a significant positive correlation with plasma levels of alpha-MSH. Plasma levels of ACTH and alpha-MSH were both positively correlated with that of cortisol. Brain [5-HIAA]/[5-HT] ratios were positively correlated with circulating plasma levels of ACTH, and a similar positive correlation was seen between [MHPG]/[NE] ratios in the optic tectum and plasma levels of ACTH, alpha-MSH and N-acetyl-beta-endorphin. In contrast, hypothalamic [MHPG]/[NE] ratios displayed a negative correlation with plasma alpha-MSH concentrations. The present study demonstrates that social stress induces skin darkening in Arctic charr and that this effect could be mediated by a stress-induced increase in the levels of alpha-MSH in the circulation. Furthermore, the results suggest that 5-HT and NE in the central nervous system could be factors regulating the pituitary release of ACTH and alpha-MSH.
- Subjects :
- Adrenocorticotropic Hormone blood
Animals
Brain Chemistry
Hydrocortisone blood
Hydroxyindoleacetic Acid analysis
Hydroxyindoleacetic Acid metabolism
Methoxyhydroxyphenylglycol analysis
Norepinephrine analysis
Serotonin analysis
Telencephalon metabolism
alpha-MSH blood
beta-Endorphin analogs & derivatives
beta-Endorphin blood
Biogenic Monoamines physiology
Brain physiology
Fishes physiology
Pro-Opiomelanocortin physiology
Skin Pigmentation
Social Dominance
Subjects
Details
- Language :
- English
- ISSN :
- 0022-0949
- Volume :
- 203
- Issue :
- Pt 11
- Database :
- MEDLINE
- Journal :
- The Journal of experimental biology
- Publication Type :
- Academic Journal
- Accession number :
- 10804161
- Full Text :
- https://doi.org/10.1242/jeb.203.11.1711