title: Neuropeptide Y (NPY)-like immunoreactivity in peripheral and central nerve fibres of the golden hamster (Mesocricetus auratus) with special respect to pineal gland innervation.
abstract: Information on the ambient lighting conditions is conveyed from the retina to the pineal organ by a neuronal pathway involving the suprachiasmatic nucleus (SCN) which acts as a circadian pacemaker. In the hamster, circadian rhythms have been shown to be influenced by injection of neuropeptide Y (NPY) into the SCN. Since NPY-immunoreactive nerve fibres are present in the rat and guinea-pig pineal glands it appeared of interest to investigate the hamster pineal as part of the circadian rhythm generating/regulating system. For comparison kidney, small intestine and cerebral cortex were studied. Like in the other rodent species so far investigated only a few of the abundant sympathetic nerve fibres in the hamster pineal gland are NPY-immunoreactive, in contrast to the relatively rich innervation of the other organs. This speaks in favour of a possible central origin of pineal NPY-immunoreactive fibres. These may either exert vasoregulatory effects on pineal vasculature or be involved in the modulation of alpha-adrenergic receptor mediated regulation of pineal metabolism.
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology*; D006224:Cricetinae; D005455:Fluorescent Antibody Technique; D007421:Intestine, Small / Q000166:cytology / Q000294:innervation*; D007668:Kidney / Q000166:cytology / Q000294:innervation*; D008297:Male; D008647:Mesocricetus; D009474:Neurons / Q000166:cytology*; D009478:Neuropeptide Y / Q000032:analysis*; D010870:Pineal Gland / Q000166:cytology*; D014018:Tissue Distribution
chemical_list: D009478:Neuropeptide Y