腹腔注射6-羟多巴胺对电针镇痛作用的影响

<正> 以往的临床和实验研究观察到针刺效果的优劣与交感神经的功能状态以及血中5羟色胺(5-HT)的含量有密切关系。为了进一步探讨外周交感神经在针刺镇痛中的作用及其途径,我们利用腹腔内注射6羟多巴胺(6-OHDA)损毁外周交感神经纤维末梢。减弱其功能活动,观察对针刺镇痛作用的影响并同时检查了血中5-HT和5羟吲哚醋酸(5-HIAA)的含量以及胃壁APUD细胞5-HT荧光强度的变化。从中分析外周交感神经的功能状态与外周5-HT的关系。

THE EFFECT OF INJECTION OF 6-HYDROXYDOPAMINE INTRAPERITONEALLY ON ACUPUNCTURE ANALGESIA

The purpose of this study was to ascertain the role of the peripheral sympathetic activity on acupuncture analgesia. 50 rats which had a comparatively stable pain threshold and a more than 50% rise of pain threshold at 10 minutes after acupuncture induction were randomly divided into three groups: 1) 30mg/kg 6-OHDA + acupuncture; 2) 100mg/kg + acupuncture; 3) Saline + acupucturel All of them, 6-OHDA and same volume of saline were administered intraperitoneally 5 days before experiment respectively. "Zusanli" and "pishu" points were electroacupunctured with 20 CPS, 2-4 mA and 60 CPS 1-2 mA respectively. The analgesia effect of electro-acupuncture was estimated by using the potassium iontophoresis tail-flick test. The content of noradrenalin (NA) in brain and the change of fluorescent intensity of NA in the peripheral sympathetic nerve terminals were determined immediately after analgesia experiment. Results were summarized as follows: In 6-OHDA groups, the fluorescent intensity of NA in the peripheral sympathetic nerve terminals in organs such as gastric wall, duodenum, heart, kidney was markedly weaker than that in saline group. But the content of NA in cortex, diencephalon and brain stem was no significantly different. It suggested that only was the majority of the peripheral sympathetic nerve terminals damaged by inject- ing 6-OHDA, under this condition, the acupuncture analgesia was notably enhanced (1.15±0.047mA - 1.46±0.088 mA, p<0.01, n=12), but in saline contral group, it was no change (1.28±0.073 mA - 1.23±0.093mA, p>0.05, n=23). The results suggested that besides central mechanism of acupuncture ana- lgesia, the excitability of the peripheral sympathetic system might be an important fact in acupuncture analgesia. In our previous studies, it had been found that acupuncture analgesia was almost simultaneous with the inhibitory effect of acupuncture on the peripheral sympathetic nerve, It is assumed that acupuncture inhibits the vasocontrction fibers of sympathetic nerve which in turn influence micrci- rculation. to change the excitability of free nerve endings, Moreover, the inhibitory effect of acupuncture on sympathetic nerve could decrease 5-HT releasing into blood from APUD cells, It might improve microcirculation and benefit the analgesia.