Presence of sst(2(a)) receptor immunoreactivity in rat ependyma and tanycytes

Somatostatin sst(2(a)) receptor was observed, by immunofluorescence, in epe ndymal cells and in tanycytes of the wall of the ventricle and the hypothal amic recess of the male rat median eminence. Strong immunoreactivity for th e receptor protein was observed in lateral tanycytes (alpha -type) while a moderate signal was seen in medial tanycytes (beta -type). In high magnific ation the immunoreactive material, of moderate intensity, had a coarse gran ular appearance. Only few of the alpha -tanycytes also displayed immunoreac tive GFAP. The apical portion of the ependymal cells as well as of tanycyte s contained immunoreactive S-100 (alpha beta). since rather high levels of somatostatin are demonstrated to occur in the cerebrospinal fluid of the th ird ventricle, it is suggested that somatostatin via the sst(2(a)) receptor may regulate the physiology of tanycytes. NeuroReport 12:1793-1797 (C) 200 1 Lippincott Williams & Wilkins.