Modulatory effect of protein kinase C activator on contractility of rat vas deferens.
The modulatory effect of the protein kinase C activator was examined on contraction of rat isolated vas deferens induced by constrictive agonists, noradrenaline (NA), ATP, BaCl2 and high K+. Phorbol 12,13-diacetate (PDA, 1 micromol/l) induced a transient extracellular Ca(2+)-dependent contraction while the inactive analogue, 4alpha-phorbol (1 micromol/l) had no effect. PDA significantly enhanced the peak amplitude of the contractile response to NA (0.1-10 micromol/l), ATP (100 micromol/l), Ba2+ (3 mmol/l) or high K+ (30 mmol/l). Staurosporine at 30 nmol/l reduced the enhancing effect of PDA on the agonist-induced contraction. NA (10 micromol/l) produced a phasic contraction followed by a sustained contraction, while ATP induced monophasic contraction. Pretreatment with nifedipine (10 nmol/l) had no effect on the phasic contraction induced by NA, but it significantly reduced ATP- or high K(+)-induced contraction. Staurosporine (30 nmol/l) alone attenuated the peak contractile response induced by NA or ATP but not by Ba2+. NA produced a transient contraction in Ca(2+)-free Krebs solution, and PDA (1 micromol/l) markedly enhanced this effect. These novel data indicate that activation of a protein kinase C-dependent mechanism not only affects contraction mediated by Ca2+ influx through voltage-sensitive Ca2+ channels, but also promotes intracellular Ca2+ release or intracellular Ca(2+)-mediated contractile mechanism in rat vas deferens.
Huang
Y
Y
Department of Physiology, Chinese University of Hong Kong, Shatin, Hong Kong, China. yu-huang@cuhk.edu.hk
Pai
R K
RK
Lau
C W
CW
Chan
F L
FL
Chen
Z Y
ZY
Yao
X Q
XQ
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D017609:Barium Compounds / Q000494:pharmacology; D002712:Chlorides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019311:Staurosporine / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects* / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D017609:Barium Compounds; D002712:Chlorides; D010703:Phorbol Esters; D014662:Vasoconstrictor Agents; C024986:barium chloride; C008874:phorbol-12,13-diacetate; D000255:Adenosine Triphosphate; D011493:Protein Kinase C; D019311:Staurosporine; D009543:Nifedipine; D011188:Potassium; D009638:Norepinephrine