Effects of phorbol 12,13-dibutyrate and H-7 in extravascular smooth muscle contraction.
The effect of the activator, phorbol 12,13-dibutyrate (PDB), and the inhibitor, H-7, of protein kinase C (PKC) has been assayed in rat uterus. PDB increases the amplitude of spontaneous contractions of rat uterus and this effect does not occur in the presence of H-7 or nifedipine. PDB did not modify the KCl-induced tonic contraction but H-7 relaxed it, in a concentration-dependent way. PDB inhibited the contraction induced by oxytocin in rat uterus incubated in Ca-free solution and relaxed the tonic contraction induced by oxytocin in this medium. The relaxing effect of PDB on oxytocin-induced contraction was not modified by H-7. Thus H-7 relaxed, in a concentration-dependent way, the tonic contractions induced by oxytocin and vanadate in the rat uterus incubated in Ca-free medium. Our results suggest a dual effect of PDB related to calcium, and a direct and PKC-independent inhibitory effect of H-7.
Fernandez
A I
AI
Departamento de Medicina, Facultad de Medicina, Oviedo, Spain.
Cantabrana
B
B
Hidalgo
A
A
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D002118:Calcium / Q000378:metabolism; D005260:Female; D007546:Isoquinolines / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010121:Oxytocin / Q000494:pharmacology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D047428:Protein Kinase Inhibitors; D051381:Rats; D017208:Rats, Wistar; D014590:Uterine Contraction / Q000187:drug effects*
D007546:Isoquinolines; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D015240:Phorbol 12,13-Dibutyrate; D010121:Oxytocin; D011189:Potassium Chloride; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D002118:Calcium