Daily patterns of Bmal1 and Rev-erb alpha in the hamster pineal gland are not controlled by norepinephrine

Per1 and Cry2 gene expression in the pineal gland increases nocturnally and is regulated by norepinephrine.

• The expression of Per1 and Cry2 mRNA levels rises at night and remains elevated in constant darkness, but is suppressed in constant light.
• Administration of the adrenergic antagonist propranolol eliminates the nocturnal increase in Per1 and Cry2 expression.
• Bmal1 and Rev-erb alpha mRNA levels show daily variation, peaking at midday and during the transition from day to night, respectively.
• The daily variation of Bmal1 and Rev-erb alpha expression is maintained in constant light and is unaffected by propranolol.
• This research confirms the role of norepinephrine in regulating Per1 and Cry2 expression while identifying a circadian rhythm for Bmal1 and Rev-erb alpha that operates independently of norepinephrine.

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