Abstract:
:Little is known about the differences in the neural substrates of circadian rhythms that are responsible for the maintenance of differences between diurnal and nocturnal patterns of activity in mammals. In both groups of animals, the suprachiasmatic nucleus (SCN) functions as the principal circadian pacemaker, and surprisingly, several correlates of neuronal activity in the SCN show similar daily patterns in diurnal and nocturnal species. In this study, immunocytochemistry was used to monitor daily fluctuations in the expression of the nuclear phosphoprotein Fos in the SCN and in hypothalamic targets of the SCN axonal outputs in the nocturnal laboratory rat and in the diurnal murid rodent, Arvicanthis niloticus. The daily patterns of Fos expression in the SCN were very similar across the two species. However, clear species differences were seen in regions of the hypothalamus that receive inputs from the SCN including the subparaventricular zone. These results indicate that differences in the circadian system found downstream from the SCN contribute to the emergence of a diurnal or nocturnal profile in mammals.
journal_name
J Biol Rhythmsjournal_title
Journal of biological rhythmsauthors
Nunez AA,Bult A,McElhinny TL,Smale Ldoi
10.1177/074873099129000713subject
Has Abstractpub_date
1999-08-01 00:00:00pages
300-6issue
4eissn
0748-7304issn
1552-4531journal_volume
14pub_type
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