[3H]5‐Hydroxytryptamine Binding to Brain Astroglial Cells: Differences Between Intact and Homogenized Preparations and Mature and Immature Cultures

Abstract

[³H]5-hydroxytryptamine ([³H]serotonin) binds with high affinity (K_D 2–12 nM) to a finite number of sites on brain astroglial cells. The number of binding sites in the C₆ glioma line is decreased significantly (B_max= 315 versus 30 fmol/mg) by homogenization. In intact primary cultures, derived from newborn rat brain, the number of binding sites is far greater in cultures of immature astrocytes than in cultures treated with dibutyryl cyclic AMP (B_max= 1,520 versus 580 fmol/mg). A role for these receptors in development is suggested.