Effects of some iontophoretically appied durgs on dorsal horn cells treated by high frequency conditioning stimulation in cats
Authors
정용
Issue Date
1992
Description
의학과/석사
Abstract
[한글]
Transcutaneous electrical nerve stimulation(TENS), 침술 등은 통증억제 목적으로 널리 사용되고 있으며 말초신경이 자극됨으로써 그 효과가 나타나는 것으로 보고된 바 있다. 그러나 말초신경자극의 변수(parameter)에 따라 진통특성 및 기전이 다른 것으로 알려져 있다. 예를 들어 저빈도, 고강도로 말초신경자극시에는 주로 endogenous opioid system의 활성화가 주요 진통 기전으로 거론되고 있으나 고빈도, 저강도로 시행하였을 경우 endogenous opioid system과 무관하게 그 진통효과가 나타나는 것으로 알려져 있다.
한편 TENS 및 전기침술은 그 시행방법이 개선됨에 따라 상기한 자극 변수외에 다양한 방법들이 이용되고 있는데 고빈도, 고강도 자극시 나타나는 진통기전에 관한 연구는 비교적 미흡한 상태이다.
따라서 본 실험에서는 고빈도, 고강도로 말초신경자극시 몇가지 신경전달물질의 길항제를 이온영동적으로 투여하여 말초신경자극에 의한 진통기전의 일부를 밝히고자 하였다.
실험결과를 요약하면 다음과 같다.
1. 척수후각세포의 spontaneous activity는 glutamate의 이온영동적 투여에 의해 증가되었고 GABA에 의해 억제되었으나 naloxone, picrotoxin, strychnine에 의해서는 영향을 받지 않았다.
2. 말초신경자극시 naloxone을 이온영동적으로 동시에 투여한 결과 척수후각세포의 통증반응 억제정도는 약물비투여군과 비교하여 의의 있는 차이를 볼 수 없었다.
3. 말초신경자극시 picrotoxin을 이온영동적으로 투여한 결과 척수후각세포의 통증반응 억제정도는 약물비투여군에 비해 자극직후에만 의의 있게 감소되었다.
4. 말초신경자극시 strychnine을 이온영동적으로 투여한 결과 척수후각세포의 통증반응 억제정도는 약물비투여군에 비해 통계적으로 유의한 차이를 보이지 않았다.
이상의 결과로 보아 고빈도, 고강도의 말초신경자극시 나타나는 진통효과에는 적어도 억제성 신경전달물질이 부분적으로 관여함을 알 수 있었다.
[영문]
Transcutaneous electrical nerve stimulation(TENS), acupuncture-needling, and electoacupuncture are useful non-ahlative methods in medical practice for relief of acute and chronic pain. These procedures appear to work by causing an increase discharge in afferent nerve fibers which in turn modifies the transmission of
impulses in pain pathways.
It is known that mechanisms of analagesic effects of these maneuvers are variable according to the stimulating parameters. For example the endogenous opioid system is profoundly related to the mechanism when the peripheral nerve stimulation is applied with parameters of low frequency and high intensity. However when the stimulation is applied with parameters of high frequency and high intensity, the reduced activity of dorsal horn cells was only slightly reversed by naloxone, a specific opiate antagonist.
Thus, the present study was performed to investigate the possible related neurotransmitters in the mechanism of peripheral nerve stimulation with parameters of high frequency and high intensity by using an iontophoretic application of some antagonists of the neurotransmitters.
The dorsal horn cell activity evoked by squeezig the peripheral cutaneous receptive field was recorded sa an index of pain with microelectrode at the lumbo-sacral spinal cord. Naloxone, picrotoxin and stychnine were applied at the same time at 200㎁ during a period of conditioning nerve stimulation and abserved
the effecs of those drug on a change of dorsal horn cell activities.
The main results of the experiment are summerized as follows:
1. The spontaneous activity of dorsal horn cells was increased by iontophoretic application of glutamate and decrease by GABA while it was not changed by naloxone, picrotoxin or strychnine.
2. When naloxone was applied iontophoretically during the peripheral nerve stimulation, the analgesic effect showed no statistically significant difference compared with the control group.
3. When picrotoxin was applied iontophoretically during the peripheral nerve stimulation, the analgesic effect was reduced and skewed statistically significant difference with the control group just after the stimulation.
4. When strychnine was applied iontophoretically during the peripheral nerve stimulation, the analgesic effect was reduced but did not skewed statistically significant difference with the control group.
These results suggest that inhibitory neurotransmitter system, at least GABAergic system may be partially related in the analgesic action of peripheral nerve stimulation with parameters of high frequency and high intensity.