SOMATOSTATIN DOES NOT AFFECT MULTIPLICATION OF GRANULE CELLS IN THE RAT CEREBELLUM

Somatostatin receptors are transiently expressed by immature granule c ells of rat cerebellum. The effects of somatostatin and octreotide on cell proliferation were studied in cultured cerebellar explants from 1 0-day-old rats. Cell multiplication was measured using [H-3] thymidine incorporation and flow cytometric analysis of cell cycle parameters. [H-3] Thymidine incorporation occurred exclusively in neuroblasts of t he external granule cell layer in the presence of insulin (1 mu M). Th e labeling index, the length of the S phase, and the potential doublin g time were similar in vivo and in explants. Octreotide (10(-12) to 10 (-6) M) had no effect on [H-3]thymidine incorporation in cerebellar ex plants. In addition, somatostatin and octreotide did not modify the pr oportion of cells in the S, G(0)-G(1), and G(2)-M phases. The present results demonstrate that somatostatin does not affect cell multiplicat ion in neurons of the external granule cell layer. (C) 1997 Elsevier S cience Inc.