AGh 是中枢重要的神经化学传递介质之一。在我们以往的工作中

曾观察到:电针的镇痛效应与大白鼠不同脑区内的 ACh 含量变化有着密切的关系

电针镇痛时

脑内ACh 含量增加;同时

ACh 的更新率加快。但是

应用代谢阻断法来观察脑内In our past work it had been demonstrated that Ach content in different regions of rat brain was incrcaced and its turnover accelerated during electro-acupuncture analgesia.However

the metabolism-block method we utilized can't completely reflect the state of Ach synthesis in brain.In present paper the Ach content in rat brain was measured by radio immunoassay(RIA)

and the amount of Ach formed in the medium for enzyme catalysis was evaluated directly with RIA at the same time for the judgement of the activity of cho- lineacetylase(ChAC)—an enzyme of Ach synthesis.In addition

the activi- ty of ChE—a hydrolase of Ach was also estimated with alkaline hydroxy amine and iron trichloride spectrophotometry in order to observe the affects of electroacupuncture and morphine analgesia on them. 1.Electroacupuncturing bilataral“Huan tiao”point for 50 min

the obvious enhancement of pain threshold was observed.At that time the Ach content in both thalamus and caudate mucleus was increased

the ChAc acti- vity was risen and the ChE activity was also increased respectively.These implied that during electroacupuncture analgesia both synthesis and release of Ach in rat brain were enhanced

but the rate of synthesis enhancement greatly exceeded that of release

thus resulting in the increase of Ach content. 2.Fifty min after intraperitoneal injection of morphine(20mg/kg)

o- bvious elevation of the pain threshold was also observed.In the meantime

the Ach content of thalamus and caudate nucleus was risen and the ChAc activity was strengthened but the ChE activity significantly was decreased respectively.This showed that during analgesia induced by morphine

the ACh synthesis in rat brain as electroacupuncture did

was accelerated also

ho- wever the releae was dicreased

thus

it greatly increased the Ach content of brain. The foregoing results indicated that during the electroacupuncture and the morphine analgesia the Ach content of brain was increased but the macha- nism responsible to their increase was somewhat different in both cases

ie: the enhancement of Ach content in brain during electroacupuncture analgesia may mainly be due to acceleration of the Ach synthesis

while the increase of Ach Content accompanied by morphine analgesia may mainly be responsi- ble for the inhibition of ACh release

However

it was in any way

disclolo- sed that the enhancement of the Ach content of brain played an importent role in both clectroacupuncture and morphine analgesia