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Neuroendocrinology of agonostic interaction and social signalling in Artic charr (Salvelinus alpinus) : Studies on the neuroendocrine regulation of aggressive behaviour, stress responses and skin colour

<p>This thesis shows that socially subordinate Arctic charr (<i>Salvelinus alpinus</i>) display elevated brain serotonergic (5-HT) and norepinephric activity along with a chronic activation of the hypothalamic-pituitary-interrenal (HPI) axis, including elevated plasma concentrations of á-MSH. Furthermore, subordinate fish showed an inhibition of aggressive behaviour and darker body coloration, skin darkness being positively correlated with plasma á-MSH. Fish kept on dark background, and thus being darker in body colour, were less aggressive than conspecifics interacting on white background, supporting the hypothesis that skin darkening could signal social submission. The 5-HT<sub>1A </sub>-receptor agonist 8-OH-DPAT stimulated HPI axis activity in non-stressed fish, but if administrated to stressed fish it inhibited HPI axis activity, suggesting that 5-HT<sub>1A</sub> receptors may act as both post- and pre-synaptic receptors. 8-OH-DPAT also induced skin darkening in both non-stressed and stressed fish. Stimulation of brain dopaminergic activity by L-dopa treatment counteracted the stress-induced inhibition of aggressive behaviour, and stress related effects on brain 5-HT activity and plasma levels of cortisol. In conclusion, social subordination in Arctic charr results in skin darkening and an inhibition of aggressive behaviour. Stress-induced effects, that could be mediated by elevated brain 5-HT activity, and serve as a way of signalling social position and coping with stress.</p>

Identiferoai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-616
Date January 2001
CreatorsHöglund, Erik
PublisherUppsala University, Department of Evolutionary Biology, Uppsala : Acta Universitatis Upsaliensis
Source SetsDiVA Archive at Upsalla University
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral thesis, comprehensive summary, text
RelationComprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 611

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