Organotypic slice culture of the suprachiasmatic nucleus

To establish an in vitro system which would enable us to observe SCN functions over a long period, we developed a new method to culture SCN tissues by means of a roller tube. Coronal slices containing the SCN were prepared from 5- to 7-day-old rat brains. Slices were maintained for several weeks in plasma clots on coverslips that were immersed in a culture medium within a rotating test tube. In this preparation, vasopressin- and vasoactive intestinal polypeptide-immunoreactive or their mRNA expressing neurons were found in the subdivisions, similar to those found in the SCN in vivo. Moreover, amounts of vasopressin released from the SCN culture into the medium revealed circadian oscillation during the 48-h sampling period. Therefore, SCN in these slice culture conditions in vitro is able to maintain for several weeks not only topographical organization but also functional integrity as a circadian pacemaker.