Analysis of nociceptive system in pathologic conditions

(1)利用犬睾丸-精索神经标本，研究佛波酯(佛波酯，PDBu)激活蛋白激酶C对多通道受体活动的影响。PDBu(&gt；=10^&lt；-7&gt；M)在长潜伏期(长于5分钟)后引起微弱而持久的兴奋。PDBu(&gt；=10^&lt；-8&gt；M)促进了热反应。在10~(-6)M时，膝关节传入也有类似的效应。缓激肽反应的抑制或促进取决于PDBu的使用方法。为了比较化学物质敏感性的差异，我们还试图开发一种使用硬膜、胸膜和肠系膜的新的体外内脏制剂。由于苏珊·布雷姆在胸膜和皮肤准备方面的经验，我们与她合作，成功地从肠系膜准备中记录了多模式受体。(2)在佐剂性炎症大鼠中，多模式受体由交感神经激活或肾上腺素注射兴奋。这种兴奋是通过α_2受体介导的，它既不依赖交感神经上的α_2受体，也不依赖于前列腺素的合成。(3)在培养的细胞中，在有或没有神经生长因子(NGF)的情况下，缓激肽(BK)和前列腺素E_2(PGE_2)对辣椒素(CAP)敏感的背根节(DRG)细胞的膜电位、膜输入阻力没有影响。BK和/或PGE_2使有NGF的CAP敏感细胞去极化，但不含NGF。BK对CAP敏感细胞的去极化作用可能是通过B_2受体，因为B_1受体激动剂不影响细胞。低浓度的PGE_2对NGF培养的DRG细胞无影响，但可增强BK的去极化作用。目前，我们有可能通过对NGF培养的DRG细胞进行细胞内记录来阐明介质对伤害性感受器膜或细胞内动力学的作用机制。

(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.