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.