Uptake and Binding of Serotonin by Primary Cultures of Mouse Astrocytes

Abstract

Primary cultures of glia contain a high glial fibrillary acidic protein level and exhbit important glutamine synthetase activity. They take up serotonin via a high affinity carrirer-mediated system with a K_m of micromolar range. The K_m of this transport process does not vary during cell growth or maturation; however, during the last period of morphological change induced by dibutyryl cyclic AMP, an increase in V_max is observed. Chlorimipramine, fluoxetine and fenfluramine at 10^-4M inhibit this uptake. ³H-5-HT still binds to partially purified astrocytic membranes on a single type of site. During growth, neither K_D nor B_max were modified. During the maturation period, K_D decreased to about 50% of its control level. Methysergide inhibits that binding.