A local nerve circuit sensitive to TTX helps control daily rhythms of PK2 and BDNF in the mouse brain's clock center

Tetrodotoxin treatment abolished the circadian rhythm of BDNF mRNA levels in the suprachiasmatic nucleus (SCN) of adult mice.

• The expression of clock genes Per1, Per2, Bmal1, and Cry1 was not affected by tetrodotoxin treatment.
• Clock-associated genes Dec1, Dec2, Rev-erbalpha, Rev-erbbeta, and DBP maintained their circadian rhythms despite tetrodotoxin application.
• Tetrodotoxin significantly dampened the circadian rhythm of PK2 mRNA levels.
• The AVP mRNA levels did not show significant changes following tetrodotoxin treatment.
• Input through sodium channel-dependent neuronal activity is not necessary for the expression of circadian rhythms of clock and clock-associated genes.

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