Ethanol enhances the in situ phosphorylation of MARCKS and protein kinase C activity in primary cultures of astrocytes

Protein kinase C (PKC) plays an important regulatory role in astrocyte function. Chronic exposure to ethanol for 4 days resulted in an increase in Ca2+-dependent PKC activity in the supernatant fraction of astrocyte homogenates. Only Ca2+ independent PKC activity could be observed in the membrane fraction and this activity was unaffected by ethanol exposure. Chronic ethanol exposure also increased the in situ phosphorylation of MARCKS in permeabilized astrocytes both in the absence or presence of the PKC activator, phorbol 12 -myristate 13 - acetate (PMA). These results suggest an increase in the expression of one or more astrocytic PKC isoforms after chronic ethanol exposure.