Analysis of nociceptive system in pathologic conditions

(1)我们研究了蛋白激酶-C激活佛波醇酯，佛波醇12，13二丁酸酯（PDBu），对多模态受体活动的影响，使用犬睾丸精索神经制剂。PDBu（&gt;=10 μ <-7>M）在长潜伏期（长于5分钟）后诱导弱但持久的兴奋。PDBu（&gt;=10 μ M）促进热响应<-8>。在膝关节传入纤维中观察到类似的作用，但在10- 6 M时，PDBu的应用方法不同，缓激肽反应被抑制或被促进。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标本，使用硬脑膜，胸膜和肠系膜。我们还邀请了Susanne Bengym，因为她在胸膜和皮肤制备方面的经验，我们与她合作，成功地从肠系膜制备中记录。(2)在急性炎症大鼠中，交感神经激活或肾上腺素注射可使多模态受体兴奋。这种兴奋是通过α_2受体介导的，它既不依赖于交感神经上的α_2受体，也不依赖于前列腺素的合成。(3)在培养24小时内，缓激肽（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、膜输入电阻无影响。BK和（或）PGE_2对有NGF的CAP敏感细胞有去极化作用，但对无NGF的CAP敏感细胞无去极化作用，BK的去极化作用可能是通过B_2受体，而B_1受体激动剂对细胞无影响。低浓度的PGE_2（对细胞无影响）可增强BK诱导的NGF诱导的DRG细胞去极化，目前我们有可能利用NGF诱导的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.