Neuroanatomical evidence for the involvement of β-endorphin during reproductive stress response in the fish Oreochromis mossambicus

Publication date: Available online 7 July 2016 Source:Journal of Chemical Neuroanatomy Author(s): Ambarisha Chabbi, C.B. Ganesh Although neuroendocrine regulation of stress response involving hypothalamo-pituitary-adrenal axis is well established in mammals, the mechanism of functioning of endocrine-stress axis is not completely elucidated in fish. Our previous studies suggested a possible role for the opioidergic mediation of reproductive stress response in fish. In the present investigation, by immunocytochemical approach, we studied the distribution of β-endorphin (β-EP) secreting neurons in the brain of the tilapia Oreochromis mossambicus exposed to aquacultural stressors. Intensely stained β-EP immunoreactive neurons were encountered in the nucleus lateralis tuberis (NLT) region during previtellogenic and vitellogenic phases in both controls and in fish exposed to aquacultural stressors. Furthermore, at the end of the prespawning phase in controls, weak staining in β-EP neurons was accompanied by intensely stained luteinizing hormone (LH) immunoreactive cells in the proximal pars distalis (PPD) of the pituitary gland and a significantly higher gonadosomatic and hepatosomatic indices, suggesting the attenuation of inhibitory effect of β-EP on reproductive axis prior to spawning. However, in fish exposed to stressors, several darkly stained β-EP immunoreactive cells with dense fibre projections towards the hypothalamo-hypophysial tract were concomitant with w...
Source: Journal of Chemical Neuroanatomy - Category: Neuroscience Source Type: research