CIRCADIAN-RHYTHMS OF VASOPRESSIN RELEASE IN PRIMARY CULTURES OF RAT SUPRACHIASMATIC NUCLEUS

We have developed a suprachiasmatic nucleus (SCN) cell culture system to study the cellular and molecular bases of the mammalian circadian p acemaker. The SCN regions were dissected from 4- to 6-day-old rat pups and dissociated cells were cultured in a defined medium. In all the c ultures, the release of vasopressin showed clear circadian oscillation , which appeared within a few days in culture and lasted for more than a month. The peak of vasopressin release was observed at subjective d ay. These findings suggest that this culture system provides a valuabl e model for elucidating the mechanism of the circadian pacemakers.