Arachidonic acid acts through protein kinase C to inhibit depolarization-induced 45Ca2+ influx.

D,-dopamine receptors extracted from bovine caudate nucleus, using the detergent cholate, have been purified to apparent homogeneity by affinity chromatography on haloperidol-Sepharose and wheat-germ agglutinin-agarose columns [ 11. In this report, we describe a preliminary comparison of purified receptor preparations derived from other D,-dopamine-receptor-rich regions of bovine brain and the pituitary gland. A mixed mitochondrial-microsomal preparation of the tissues studied was solubilized using a sodium cholate (0.3% w/v)/sodium chloride ( I M) combination and purified in a stepwise manner on a haloperidol type 11or spiperone type I-affinity column [2, 31, followed by wheat-germ agglutinin-agarose chromatography [ I ] . The resulting purified D>-dopamine-receptor preparations were compared by stereospecific [ ,H]spiperone binding and SDS/PAGE analysis [ I ] . Bovine cerebellum was adopted as a control tissue, with no detectable D,-dopamine receptor present in the