Protein kinase C-mediated contractile response of the rat vas deferens.
The role of protein kinase C (PKC) in mediating contractile responses in the rat vas deferens was studied. Phorbol-12,13-diacetate (PDA) in the presence of 20 mM K+ elicited a concentration-dependent response with an EC50 of 190 nM. The non-PKC activator 4 alpha-phorbol (2 microM) was unable to elicit contraction in 20 mM K+ buffer. Incubation of rat vas deferens with the PKC inhibitor iso-H7 (30 microM) attenuated the response to norepinephrine (NE) and neurokinin A, with maximal effects depressed to 42 and 39% of control, respectively. Responses to 60 mM K+ and 2 microM PDA (20 mM K+) was also significantly inhibited by iso-H7. In the presence of 2 microM PDA and 20 mM K+, the NE concentration-effect curve was shifted 3.6-fold to the right of the control curve in a parallel manner. 4 alpha-Phorbol (20 mM K+) at the same concentration did not produce this effect. These results suggest a significant role for PKC in the contractile response of the rat vas deferens.
Abraham
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Department of Pharmacology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614.
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D000704:Analysis of Variance; D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D015288:Neurokinin A / Q000502:physiology; D009638:Norepinephrine / Q000502:physiology; D010703:Phorbol Esters / Q000494:pharmacology*; D011188:Potassium / Q000502:physiology; D011493:Protein Kinase C / Q000502:physiology*; D051381:Rats; D014649:Vas Deferens / Q000187:drug effects
D010703:Phorbol Esters; C008874:phorbol-12,13-diacetate; D015288:Neurokinin A; D011493:Protein Kinase C; D011188:Potassium; D009638:Norepinephrine