Expression of prokineticin receptors in mouse cultured astrocytes and involvement in cell proliferation

Effects of prokineticins (PKs), a novel family of bioactive peptides with a mitogenic action to endothelial cells of the endocrine gland and testis, on astrocytic functions were examined. Mouse cultured astrocytes expressed PK-R1 type PK receptors, while there was little expression of the PK-R2 type. PKs caused increases in astrocytic cytosolic Ca2+ levels and BrdU incorporation. Increases in Ca2+ levels by PK-2 were diminished by U73122 (a phospholipase C inhibitor). PK-induced BrdU incorporation was inhibited by U73122, GF109203 (a protein kinase C inhibitor) and PD98059 (a MEK/ERK inhibitor). These results indicate that PK receptors are expressed in astrocytes and regulate astrocytic proliferation.