Bradykinin and vasopressin both stimulate phosphoinositide turnover in astrocytes in high serum- and low serum-containing media but have no effect on [3H]thymidine incorporation

Astrocytes were obtained from rat cerebral cortices and cultured for 10 days in Dulbecco's modified Eagle's medium (DMEM) and 10% fetal calf serum (FCS). Cell division was arrested by transfer to low serum (0.1%)-containing medium for 24 h. Subsequently the neuropeptides bradykinin and vasopressin; previously shown to induce inositol phospholipid turnover, were added at 10 μM concentrations for a further 24 h, after which time the cultures were pulsed with [3H]thymidine to measure the rate of incorporation of the label due to receptor stimulation. By adding back 10% FCS or phorbol-12-myristate-13-acetate (PMA) at 1 μ/ml concentrations the rate of [3H]thymidine incorporation was increased while both bradykinin and vasopressin had no effect on the rate of [3H]thymidine incorporation into astrocytes. Further studies examined the effects on inositol phospholipid turnover in cortical astrocytes upon stimulation with bradykinin and vasopressin in both 10% FCS and 0.1% FCS. Both peptides stimulated phosphoinositide turnover under the two conditions although the response to bradykinin was reduced in 0.1% FCS.