Daily cycle of melatonin release in pineal gland cells: arginine vasopressin reduces melatonin production

AVP (1 microM) suppressed melatonin release from pineal gland explant cultures.

• Melatonin release is regulated by AVP, which is released from the suprachiasmatic nucleus.
• Noradrenaline, which normally stimulates melatonin release, has its effect reduced by AVP.
• Melatonin levels in the suprachiasmatic nucleus are higher during the dark period compared to the light period.
• This pattern of melatonin expression persists even under constant dim light conditions.
• The findings suggest a reciprocal regulatory relationship between melatonin and AVP in the SCN and pineal gland.

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