Lanthanum potentiation of the vascular response to a protein kinase C activator in genetically hypertensive rats.
The effects of lanthanum on the contraction induced by the protein kinase C activator, 12-O-tetradecanoylphorbol-13-acetate (TPA) were studied in femoral artery rings from stroke-prone, spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto rats (WKY). When exposed to a calcium-free buffer containing 1 mmol/l EGTA, the femoral artery rings from SHRSP and WKY, pre-contracted with TPA (10(-6) mol/l), relaxed by 52 and 24%, respectively. Treatment of the rings in this calcium-free buffer with 2.6 mmol/l lanthanum significantly potentiated the TPA-induced contractions in vascular rings from WKY (49%) and SHRSP (136%). Potentiation by lanthanum of the TPA-induced contraction in the absence of extracellular calcium suggests that this cation is acting intracellularly to increase protein kinase C activity. The increased vascular responsiveness of SHRSP to lanthanum may reflect an abnormality in protein kinase C activation in vascular smooth muscle of genetically hypertensive rats.
Raval
J
J
Department of Physiology, University of Michigan, Ann Arbor 48109.
Joshua
I G
IG
Webb
R C
RC
Bohr
D F
DF
D000818:Animals; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D006973:Hypertension / Q000201:enzymology / Q000503:physiopathology*; D066298:In Vitro Techniques; D007811:Lanthanum / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D007811:Lanthanum; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate