Photic regulation of circadian rhythms and the expression of p75 neurotrophin receptor immunoreactivity in the suprachiasmatic nucleus in rats.
Neurotrophic factors have been implicated in the mechanism underlying photic regulation of circadian rhythms in mammals. In rats, the most abundant neurotrophin receptor found in the suprachiasmatic nucleus (SCN), the circadian clock, is the low affinity p75 neurotrophin receptor (p75NTR). This receptor is expressed by retinal afferents of the SCN, but nothing is known about its role in photic regulation of circadian rhythms. We show here that neonatal treatment with the retinal neurotoxin, monosodium glutamate (MSG), which has no effect on photic entrainment of circadian rhythms, nearly completely abolished p75NTR immunoreactivity in the SCN in rats. These findings suggest that p75NTR from retinal sources do not play an essential role in the mechanism mediating photic entrainment of circadian rhythms in rats.
Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, H3G 1M8, Montréal,Québec, Canada.
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Beaulé
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Amir
D000818:Animals; D000906:Antibodies; D002940:Circadian Rhythm / Q000502:physiology*; D005503:Food Additives / Q000633:toxicity; D007150:Immunohistochemistry; D009410:Nerve Degeneration / Q000139:chemically induced / Q000378:metabolism; D010775:Photic Stimulation; D051381:Rats; D017208:Rats, Wistar; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000032:analysis* / Q000096:biosynthesis* / Q000276:immunology; D012160:Retina / Q000473:pathology; D012970:Sodium Glutamate / Q000633:toxicity; D013493:Suprachiasmatic Nucleus / Q000737:chemistry / Q000378:metabolism*
D000906:Antibodies; D005503:Food Additives; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D012970:Sodium Glutamate