The cooperation between the influx of extracellular calcium and alpha1-adrenoceptor-induced translocation of protein kinase C.
Calcium ionophore A23187 or phenylephrine injected i.p. in doses of 0.05-0 .25 mg kg-1 and 0.1-1 mg kg-1, respectively, induced translocation of protein kinase C (PKC) from the cytosol to the membrane fraction of the rat frontal cortex and hippocampus. The action of A23187 was blocked in a dose-dependent manner by nifedipine and verapamil. The phenylephrine induced translocation of PKC was blocked by prazosin and in a dose-dependent manner by nifedipine and verapamil. In contrast, pre-treatment with a small, ineffective by itself, dose of A23187 (0.02 mg kg-1) potentiated the alpha1-adrenoceptor induced translocation of PKC. Thus, it seems that the influx of calcium ions through an L-type calcium channel is probably necessary for a full alpha1-adrenoceptor mediated activation and translocation of PKC.
Szmigielski
A
A
Department of Pharmacodynamics, Medical University, Muszynskiego 1, Lodz, 90-145, Poland.
Szmigielska
H
H
Zalewska-Kaszubska
J
J
Marczak
G
G
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007476:Ionophores / Q000494:pharmacology; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D015220:Calcium Channels; D007476:Ionophores; D018340:Receptors, Adrenergic, alpha-1; D010656:Phenylephrine; D000001:Calcimycin; D011493:Protein Kinase C; D002118:Calcium