Analysis of nociceptive system in pathologic conditions

(1)利用犬睾丸-精索神经制剂研究了phorbol酯phorbol 12,13 dibutyrate （PDBu）活化蛋白激酶- c对多模态受体活性的影响。PDBu （>=10^<-7>M）在长潜伏期（大于5 min）后引起弱而持久的兴奋。PDBu （>=10^<-8>M）促进了热响应。在膝关节传入神经中观察到类似的效果，但在10-6M。不同的应用方法可抑制或促进缓激肽反应。为了比较对化学物质的敏感性差异，我们还尝试开发一种新的体外内脏制剂，使用硬脑膜、胸膜和肠系膜。在与Susanne Brehm的合作下，由于她在胸膜和皮肤准备方面的经验，我们还邀请了她到我们的实验室，我们成功地从肠系膜准备中进行了记录。(2)佐剂炎症大鼠多模态受体可通过交感神经激活或肾上腺素注射被激活。这种兴奋是通过α _2受体介导的，不依赖交感神经上的α _2受体，也不依赖前列腺素的合成。(3)培养细胞24h内。在有无神经生长因子（NGF）作用下，缓激素（BK）和前列腺素E_2 （PGE_2）对辣椒素（CAP）敏感的背根神经节（DRG）细胞的膜电位和膜输入阻抗均无影响。BK和/或PGE_2去极化的cap敏感细胞与NGF培养48小时，而不是没有NGF。bk诱导的去极化可能是通过b2受体，因为b1受体激动剂不影响细胞。低浓度的PGE_2在不影响细胞的情况下，增强了bk诱导的NGF细胞去极化。目前，我们很有可能利用NGF培养的DRG细胞的细胞内记录来阐明介质对伤害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.