REEH P.w. University of Erlangen/Nurnberg professor, 生理学部, 教授
HANDWERKER H.o. University of Erlangen/Nurnberg professor, 生理学部, 教授
MESSLINGER K. University of Wurzburg Lecturer, 生理学部, 講師
SCHMIDT R.f. University of Wurzburg professor, 生理学部, 教授
KASAI Masanori Research Institute of Environmental Medicine, Nagoya University.Assistant, 環境医学研究所, 助手 (30202005)
SATO Jyun Research Institute of Environmental Medicine, Nagoya University.Assistant, 環境医学研究所, 助手 (00235350)
MIZUMURA Kazue Research Institute of Environmental Medicine, Nagoya University.Associate Profes, 環境医学研究所, 助教授 (00109349)
(1) We studied effects of protein kinase-C activation by a phorbol ester, phorbol 12,13 dibutyrate (PDBu), on the polymodal receptor activities using canine testis-spermatic nerve preparations. PDBu (>=10^<-7>M) induced a weak but long-lasting excitation after long latency (longer than 5 min). The heat response was facilitated by PDBu (>=10^<-8>M). The similar effect was observed in knee joint afferents but at 10-6M.The bradykinin response was either suppressed or facilitated depending of application method of PDBu. To compare difference in sensitivities to chemical substances, we also tried to develop a new in vitro visceral preparation using dura, pleura, and mesentery. In cooperation with Susanne Brehm, whom we additionally invited to our lab because of her experience in pleura and skin preparations, we succeeded to record from mesentery preparations.
(2) In adjuvant-inflamed rats, polymodal receptors were excited by sympathetic activation or epinephrine injection. It was also demonstrated that this excitation is mediated through alpha_2 receptor, and it depends neither on the alpha_2 receptor on the sympathetic nerve nor on prostaglandin synthesis.
(3) In cultured cell within 24 hr.with and without nerve growth factor (NGF), the bradykinin (BK) and prostagrandin E_2 (PGE_2) did not affect membrane potential, membrane input resistance of capsaicin (CAP)-sensitive dorsal root ganglion (DRG) Cells. BK and/or PGE_2 depolarized CAP-sensitive cells cultured for 48 hrs with NGF but not without NGF.The BK-induced depolarization might be through B2-receptors, since the B1-receptor agonist did not affect the cells. A low concentration of PGE_2, which did not afffect the cells, enhanced the BK-induced depolarization in cultured cells with NGF.At present we have a good possibility to clarify the mechanisms of action of mediators on nociceptor membrane or intracellular dynamics using intracellular recording from DRG cells cultured with NGF.