| 摘要: | 針刺鎮痛及針刺麻醉的機轉,近幾十年來有許多學者持續地進行研究,而隨著疼痛機轉的不斷瞭解,針刺鎮痛的機轉亦被證實與中樞神經系統中的神經Enkephalin、Endorphin及單胺類物質5-HT、NE的濃度有關。本研究利用福馬林試驗來探討三種不同頻率(2Hz、10Hz、100Hz)電針鎮痛機轉與單胺神經原及類鴉片接受體之間的關係;更進一步利用高效液相色層分析儀(HPLC)來測定三種不同頻率電針對於腦內單胺物質的影響。 結果顯示:(1)5-HT 10.mu.g/kg、30.mu.g/kg (i.c.v.)可加強高頻100Hz電針之對於中樞鎮痛作用;而30.mu.g/kg可加強不同頻率之周邊鎮痛作用。NE3、10、30.mu.g /kg(i.c.v.)皆可加強高頻(100Hz)之鎮痛作用。(2)PCPA(i.p.)可逆轉三種頻率電針之鎮痛效果;5-HTP(i.p.)則加強三種頻率電針之鎮痛效果;而.alpha.-MT可加強高頻率(100Hz)電針對中樞之鎮痛作用及三種頻率電針對周邊之鎮痛作用。(3)Naloxone可逆轉2Hz和10Hz電針在中樞之鎮痛效應,但無法逆轉高頻(100Hz)之作用;而Naltrindole則逆轉10Hz 和100Hz電針在中樞之鎮痛效應,但無法逆轉低頻(2Hz)之作用。(4)Prazosin(i.p.)及Clonidine(i.p.)皆可加強三種頻率電針之鎮痛作用,然而Yohimbine(i.p.)則會逆轉2Hz及10Hz之電針鎮痛作用,但卻加強100Hz之電針鎮痛作用。(5)Pindobind-5-HT1A及LY-278584皆會逆轉三種頻率電針之鎮痛作用,而Ketanserin則加強了100Hz電針之鎮痛作用。更由不同頻率電針發現會影響腦內不同的單胺類物質。由以上結果顯示,三種頻率之電針鎮痛機轉,與單胺類物質NE及5-HT皆有關,在電針後5-HT 主要可能經由5-HT1A及5-HT3接受體來媒介,而高頻率電針可能還有5-HT2接受體的參與;在腎上腺素系統中則.alpha.1 及.alpha.2接受體皆有參與,且可能扮演著相反的角色。另外,在低頻率(2Hz)電針刺激下與.mu.-類鴉片接受體的關係較密切,而高頻率 (100Hz)的刺激則與.delta.-類鴉片接受體較有關。
There are many studies on the mechanism of antinociception of electroacupuncture (EAc) in the past decades. It has been proved that antinociception of EAc was related to the concentration of neuropeptides (enkephalin, endorphin) and monoamines (5HT, NE). In order to understand the relationships of different frequencies of EAc analgesia on monoaminergic neurons and opioid receptors, this study was accomplished by the formalin test in ICR mice. The brain concentrations of endogenous monoamines were determined by HPLC. The evidences suggest that (1) Exogenous 5-HT and NE enhanced the analgesic effect of the different frequencies of EAc, especially at 100Hz. (2) The antinociception of EAc at different frequencies stimulation (2, 10 and 100Hz) were attenuated by PCPA, and were potentiated by 5-HTP. (3) Naloxone could reverse the EAc analgesia of 2Hz and 10Hz but not 100Hz. However, natrindole could reverse the EAc analgesia of 10Hz and 100Hz but not 2Hz. (4) Prazosin and clonidine could potentiate the antinociception of different frequencies of EAc whereas yohimbine could reverse 2Hz and 10Hz EAc analgesia and potentiate 100Hz EAc analgesia. (5) Pindobind-5-HT1A and LY-278584 could reverse the three different frequencies of EAc analgesia and ketanserine potentiate 100Hz EAc analgesia. The concentrations of brain endogenous monoamines were influenced by different frequencies of electroacupuncture. From the above results, we suggest that the analgesic effect of EAc is related to serotonergic and noradrenergic neurons at different frequency stimulation. In serotonergic pathway, EAc analgesia may be mediated via 5-HT1A and 5-HT3 receptors. Besides, 5-HT2 may be involved in high frequency EAc analgesia. In noradrenergic pathway, both .alpha.1 and .alpha.2 receptors were involved in EAc analgesia and may be play in the opposite function. Moreover, the EAc analgesia may be mediated via .mu.-opioid receptor at low frequency stimulation and .delta.-opioid receptor at high frequency stimulation. |
