How calcium affects gene activity triggered by isoproterenol in the mouse pineal gland

Stimulation of beta-adrenergic receptors increases nighttime levels of the Aa-Nat gene responsible for melatonin synthesis in mouse pineal gland.

• A cAMP analog increased Aa-Nat gene expression at any time of day but required ionomycin for this effect.
• Isoproterenol stimulation was found to increase intracellular free calcium levels at night, contradicting earlier findings.
• Calcium depletion, whether intra- or extracellular, suppressed both calcium responses and Aa-Nat gene expression induced by isoproterenol.
• Basal intracellular calcium levels were observed to be lower during night hours, with enhanced responses to isoproterenol and KCl depolarization.
• Cryptochrome mutant mice showed no significant difference in day versus night basal calcium levels or isoproterenol responses.
• These findings indicate that the endogenous pineal clock may regulate basal calcium levels, affecting cellular responses and homeostasis.

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