The morphological differentiation of cultured astrocytes induced by ionomycin: lack of dependence on protein kinase C activation.

In a previous paper we have shown that the calcium ionophores, A23187 and ionomycin, induce a morphological differentiation of cultured astrocytes to a process-bearing form. As A23187 is known to induce the turnover of inositol phospholipids in astrocytes, and this response is dependent on extracellular calcium, we examined the morphological effects of exposure of cells to protein kinase C activators. 1,2-Dioctanoyl-sn-glycerol, mezerein and various phorbol esters are shown to result in no alteration in the morphology of cultured astrocytes. The results suggest that the morphological response of cultured astrocytes to calcium ionophores is not dependent on activation of protein kinase C.