Fukuhara et al., Neurosci Lett 2001
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We used semi-quantitative in situ hybridization to determine the effect of NPY on circadian clock genes, Period 1 (Per1) and Period 2 (Per2), expression in SCN slices ... These results suggest that NPY may induce phase shifts by mechanisms involving or resulting in reduction of Per1 and Per2 mRNA levels
Gamble et al., Eur J Neurosci 2006
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NPY significantly reduced Per1 mRNA levels induced by the light pulse