Evidence that protein kinase C activation is involved in the excitatory and facilitatory effects of bradykinin on canine visceral nociceptors in vitro.
The involvement of protein kinase (PK) C activation in the effects of bradykinin (BK) on peripheral nociceptors, polymodal receptors, was examined using canine testis-spermatic nerve preparations in vitro. Phorbol 12,13-dibutyrate 0.1 microM, which activates PKC, suppressed the BK-induced excitation when applied for 3-5 min prior to BK application, but facilitated it when applied simultaneously with BK. Neither effect was induced by an inactive phorbol ester, 4alpha-phorbol 12, 13-didecanoate, demonstrating that both effects were mediated through the activation of PKC. In addition, staurosporine 1 microM, a PK inhibitor, suppressed both BK-induced excitation and facilitation of the heat response of testicular polymodal receptors without influencing on-going activities and the heat response itself. These results suggest that PKC activation is involved in the excitatory and facilitatory effects of BK on peripheral nociceptors.
Mizumura
K
K
Department of Neural Regulation, Research Institute of Environmental Medicine, Nagoya University, Japan.
Koda
H
H
Kumazawa
T
T
D000222:Adaptation, Physiological; D000818:Animals; D001920:Bradykinin / Q000819:agonists / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004285:Dogs; D008297:Male; D009431:Neural Conduction; D009619:Nociceptors / Q000187:drug effects*; D010146:Pain / Q000503:physiopathology; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000502:physiology*; D012684:Sensory Thresholds; D019311:Staurosporine / Q000494:pharmacology; D013696:Temperature; D013737:Testis / Q000294:innervation*; D017833:Visceral Afferents / Q000187:drug effects*
D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C; D019311:Staurosporine; D001920:Bradykinin