Zon Gang, Yi Qingcheng, Wu Shixiang, Lu Yixin Wang Fansheng, Yu Yuegui, Ji Xinquan, Zhang Zuxuan, Zhao Dandan (Shanghai Institute of Materia Medica, Academia Sinica, and Shanghai Research Institute for Hypertension)
Both naloxone reversal and alterations in total endorphin content (measured by radioreceptor assay, RRA) implicated a role of endorphins in acupuncture analgesia. Since there are more than one kind of endorphin differing in distribution and probably function, it seemed necessary to study the role of these peptides separately. Therefore, we set up a radioimmunoassay (RIA) for met-enkephalin (MEK) and leu-enkephalin (LEK), the main endorphins in the brain. Working dilution of the antisera were 1: 5,000, cross reaction less than 4%. The smallest measurable quantity of MEK was 130 that of LEK 18
1. Alterations in brain regional contents of enkephalins by acupuncture: The amounts of enkephalins in both rabbit and rat brains were highest in striatum and hypothalamus, next in brainstem and cortex, and lowest in thalamus and hippocampus. LEK was higher than MEK in rabbits, but just the reverse in rats.
Both manual acupuncture in rabbits and electric acupuncture in rats induced an increase of enkephalins in striatum (P<0.001) and hypothalamus (P<0.05).
2. Enhancement of acupuncture analgesia with concomittant increase of enkephalins in striatum and hypothalamus by intraventricular bacitracin: The degradation of enkephalins in brain is very rapid. The shortness of acupuncture analgesia in animals might well be attributed to the rapid destruction of enkephalins released. To test this hypothesis, the peptidase inhibitor bacitracin was employed. Intraventricular injection of 50 µg bacitracin alone in rabbits showed no analgesic action, but greatly prolonged the analgesic effect of manual acupuncture. Pain threshold remained high 30-40 minutes after the withdrawal of needles, while in the saline acupuncture group, pain threshold already decreased at this time. Brain regional contents of LEK and MEK were estimated. The amounts in striatum and hypothalamus were much higher than the saline acupuncture and bacitracin control groups. This was especially conspicuous in striatum, where the enkephalin contents in bacitracin acupuncture group were 2-3 times that of the bacitracin control. The prolongation of acupuncture analgesia by bacitracin could be antagonized by intravenous naloxone, indicating the enhancement was due to endogenous morphine-like substances. These experiments substantiated, for the first time from the approach of retarding degradation, the role of enkephalins in acupuncture analgesia.
3. Effects of surgical isolation of basal hypothalamus on its MEK content and acupuncture analgesia: The alterations of enkephalin contents were most prominent in striatum and hypothalamus during acupuncture analgesia as shown in above experiments. A great deal of studies have been carried out on the role of striatum in acupuncture analgesia, comparatively less on hypothalamus in this respect. Immunocytochemical studies have shown that á-endorphin containing nerve cell bodies resided exclusively in the hypothalamus. In order to access the role of hypothalamic endorphinergic neurones in acupuncture analgesia, the Halasz knife was used to isolate the hypothalamus from the rest of the rat brain. Rats were divided into 5 groups, i.e., control, hypothalamus isolation, hypothalamus isolation plus electric acupuncture, sham operation, sham operation plus electric acupuncture. It was found that surgical isolation of basal hypothalamus did not affect the MEK content therein, indicating the presence of local enkephalinergic neurones within the basal hypothalamus, and that analgesic effect was attenuated but not eliminated, suggesting a role of hypothalamus in acupuncture analgesia. Electric acupuncture no longer increased MEK content in the basal hypothalamus after isolation, indicating the incoming nervous impulses were essential for the elevation of enkephalin content by acupuncture.
4. Increased levels of endorphins in the cisternal CSF of rabbits in acupuncture analgesia: To see whether endorphins were also released in the supraspinal level, we have estimated cisternal CSF contents of total endorphins and two enkephalins by RRA and RIA respectively.
The RRA experiments consisted of 20 rabbits equally distributed into control, manual or electric acupuncture, and electric stimulation of central gray groups. After these manoeuvres, 1 ml of CSF was collected from each rabbit by cisternal puncture under local anesthesia, and subjected to Sephadex G-10 column chromatography. Eluates before the salt peak were combined and designated as fraction I and those behind as fraction II. Morphine-like activities in fraction I of manual or electric acupuncture, and brain stimulation groups were found to be 22%, 31% and 20% higher than the control group, while those of fraction II were 20%, 15% and 2% higher than the control group. The data were rather dispersed, therefore of no statistical significance.
The RIA experiments consisted of 15 rabbits equally divided into control, intraventricular 50 µg bacitracin and intraventricular 50 µg bacitracin plus manual acupuncture groups. Bacitracin was employed to delay the enzymatic degradation of enkephalins. Bacitracin injection alone had no prominent effect, but bacitracin plus manual acupuncture increased enkephalin contents enormously, being 3 times that of the control group. These results indicate that in the resting state, enkephalinergic neurones are in a low level of activity, but are greatly activated by acupuncture. The wider dispersion of data in RRA experiments were probably due to the instability of enkephalins.
CLINICAL RESEARCH
ON
ACUPUNCTURE AND
MOXIBUSTION
Both naloxone reversal and alterations in total endorphin content (measured by radioreceptor assay, RRA) implicated a role of endorphins in acupuncture analgesia. Since there are more than one kind of endorphin differing in distribution and probably function, it seemed necessary to study the role of these peptides separately. Therefore, we set up a radioimmunoassay (RIA) for met-enkephalin (MEK) and leu-enkephalin (LEK), the main endorphins in the brain. Working dilution of the antisera were 1: 5,000, cross reaction less than 4%. The smallest measurable quantity of MEK was 130 that of LEK 18
1. Alterations in brain regional contents of enkephalins by acupuncture: The amounts of enkephalins in both rabbit and rat brains were highest in striatum and hypothalamus, next in brainstem and cortex, and lowest in thalamus and hippocampus. LEK was higher than MEK in rabbits, but just the reverse in rats.
Both manual acupuncture in rabbits and electric acupuncture in rats induced an increase of enkephalins in striatum (P<0.001) and hypothalamus (P<0.05).
2. Enhancement of acupuncture analgesia with concomittant increase of enkephalins in striatum and hypothalamus by intraventricular bacitracin: The degradation of enkephalins in brain is very rapid. The shortness of acupuncture analgesia in animals might well be attributed to the rapid destruction of enkephalins released. To test this hypothesis, the peptidase inhibitor bacitracin was employed. Intraventricular injection of 50 µg bacitracin alone in rabbits showed no analgesic action, but greatly prolonged the analgesic effect of manual acupuncture. Pain threshold remained high 30-40 minutes after the withdrawal of needles, while in the saline acupuncture group, pain threshold already decreased at this time. Brain regional contents of LEK and MEK were estimated. The amounts in striatum and hypothalamus were much higher than the saline acupuncture and bacitracin control groups. This was especially conspicuous in striatum, where the enkephalin contents in bacitracin acupuncture group were 2-3 times that of the bacitracin control. The prolongation of acupuncture analgesia by bacitracin could be antagonized by intravenous naloxone, indicating the enhancement was due to endogenous morphine-like substances. These experiments substantiated, for the first time from the approach of retarding degradation, the role of enkephalins in acupuncture analgesia.
3. Effects of surgical isolation of basal hypothalamus on its MEK content and acupuncture analgesia: The alterations of enkephalin contents were most prominent in striatum and hypothalamus during acupuncture analgesia as shown in above experiments. A great deal of studies have been carried out on the role of striatum in acupuncture analgesia, comparatively less on hypothalamus in this respect. Immunocytochemical studies have shown that á-endorphin containing nerve cell bodies resided exclusively in the hypothalamus. In order to access the role of hypothalamic endorphinergic neurones in acupuncture analgesia, the Halasz knife was used to isolate the hypothalamus from the rest of the rat brain. Rats were divided into 5 groups, i.e., control, hypothalamus isolation, hypothalamus isolation plus electric acupuncture, sham operation, sham operation plus electric acupuncture. It was found that surgical isolation of basal hypothalamus did not affect the MEK content therein, indicating the presence of local enkephalinergic neurones within the basal hypothalamus, and that analgesic effect was attenuated but not eliminated, suggesting a role of hypothalamus in acupuncture analgesia. Electric acupuncture no longer increased MEK content in the basal hypothalamus after isolation, indicating the incoming nervous impulses were essential for the elevation of enkephalin content by acupuncture.
4. Increased levels of endorphins in the cisternal CSF of rabbits in acupuncture analgesia: To see whether endorphins were also released in the supraspinal level, we have estimated cisternal CSF contents of total endorphins and two enkephalins by RRA and RIA respectively.
The RRA experiments consisted of 20 rabbits equally distributed into control, manual or electric acupuncture, and electric stimulation of central gray groups. After these manoeuvres, 1 ml of CSF was collected from each rabbit by cisternal puncture under local anesthesia, and subjected to Sephadex G-10 column chromatography. Eluates before the salt peak were combined and designated as fraction I and those behind as fraction II. Morphine-like activities in fraction I of manual or electric acupuncture, and brain stimulation groups were found to be 22%, 31% and 20% higher than the control group, while those of fraction II were 20%, 15% and 2% higher than the control group. The data were rather dispersed, therefore of no statistical significance.
The RIA experiments consisted of 15 rabbits equally divided into control, intraventricular 50 µg bacitracin and intraventricular 50 µg bacitracin plus manual acupuncture groups. Bacitracin was employed to delay the enzymatic degradation of enkephalins. Bacitracin injection alone had no prominent effect, but bacitracin plus manual acupuncture increased enkephalin contents enormously, being 3 times that of the control group. These results indicate that in the resting state, enkephalinergic neurones are in a low level of activity, but are greatly activated by acupuncture. The wider dispersion of data in RRA experiments were probably due to the instability of enkephalins.
CLINICAL RESEARCH
ON
ACUPUNCTURE AND
MOXIBUSTION
No comments:
Post a Comment