Wang S, Mo W Y
Sheng Li Xue Bao. 1989 Apr;41(2):128-35.
With electric stimulation of the splanchnic nerve or the skin of the tip of rabbit's ear to measure visceral or somatic pain threshold, we studied the effects of noradrenaline microinjection into the septal nucleus on visceral pain and somatic pain and the relationship between the intraseptal noradrenaline and the intra-PAG opiate peptidergic system. There was no effect on visceral pain threshold after injections of alpha-agonist clonidine (10 micrograms/2 microliters) or alpha-antagonist phentolamine (10 micrograms/2 microliters). In a group injected with beta-agonist isoprenaline (1 micrograms/2 microliters), visceral pain threshold was raised remarkably, while beta-antagonist propranolol (10 micrograms/2 microliters) injected into bilateral septal nuclei decreased visceral pain threshold. Phentolamine (10 micrograms/2 microliters) or propranolol (10 micrograms/2 microliters) injected into septal nucleus induced an elevation of somatic pain threshold. The results indicate that the beta-receptor in spetal nucleus plays an important role in the modulation of visceral pain. Both alpha-and beta- adrenergic receptors have effects on the modulation of somatic pain. Intra-PAG microinjection of naloxone (1 micrograms/1 microliters) attenuated visceral analgesia produced by injection of isoprenaline (1 micrograms/2 microliters) into septal nucleus. Microinjection of anti-leu-enkephalin antiserum (1:20,000) into PAG also attenuated the analgesia. When microinjection of isoprenaline into septal nucleus produced analgesia, the release of leu-enkephalin immunoreactive-like-substance in PAG was significantly increased. The results suggest that the analgesic effect of intra-septal noradrenaline on visceral pain is somehow related with the endogenous opiate peptidergic system in PAG, and the leu-enkephalin in PAG plays an important role in this process.
通过电刺激兔内脏神经或兔耳尖皮肤来测量内脏痛阈或躯体痛阈，我们研究了向隔核微量注射去甲肾上腺素对内脏痛和躯体痛的影响以及隔核内去甲肾上腺素与中脑导水管周围灰质（PAG）内阿片肽能系统之间的关系。注射α-激动剂可乐定（10微克/2微升）或α-拮抗剂酚妥拉明（10微克/2微升）后，内脏痛阈没有变化。在注射β-激动剂异丙肾上腺素（1微克/2微升）的一组中，内脏痛阈显著升高，而向双侧隔核注射β-拮抗剂普萘洛尔（10微克/2微升）则降低了内脏痛阈。向隔核注射酚妥拉明（10微克/2微升）或普萘洛尔（10微克/2微升）可使躯体痛阈升高。结果表明，隔核中的β-受体在调节内脏痛中起重要作用。α-和β-肾上腺素能受体均对躯体痛的调节有影响。向PAG内微量注射纳洛酮（1微克/1微升）减弱了向隔核注射异丙肾上腺素（1微克/2微升）所产生的内脏镇痛作用。向PAG内微量注射抗亮氨酸脑啡肽抗血清（1:20,000）也减弱了镇痛作用。当向隔核微量注射异丙肾上腺素产生镇痛作用时，PAG中亮氨酸脑啡肽免疫反应样物质的释放显著增加。结果提示，隔核内去甲肾上腺素对内脏痛的镇痛作用与PAG中的内源性阿片肽能系统有一定关系，且PAG中的亮氨酸脑啡肽在这一过程中起重要作用。
