*A summary of studies in this institute
He Lianfang, Xu Shaofen (Research Department of Acupuncture Analgesia, Shanghai First Medical College)
Jiang Chengchuan (Huashan Hospital, Shanghai First Medical College)
This paper gives a short account of investigations made on the role of the caudate nucleus in acupuncture analgesia.
Electrophoresis of potassium ion to the skin of the rabbit's ear, served as the noxious stimulus. The minimal electric current in mA that produced the defence reaction of the head and limbs was taken as the pain threshold. It was found that the pain threshold rose significantly when the dorsal part of the head of the caudate nucleus was stimulated through chronically implanted electrodes. In clinical observations it was found that caudate stimulation brought forth alleviation of intractable pain of the patients caused by late malignancies. The characteristics of analgesia produced by caudate stimulation, such as pain relief after certain period of induction, after-effect after cessation of stimulation, calmness and wide spread analgesic effect without clear segmental topography were similiar to those of acupuncture analgesia by needling distal points. Further study in rabbits demonstrated that caudate stimulation was able to enhance the analgesic effect of electric needling, while caudate lesion resulted in attenuation of it.
Potentials evoked by electrostimulation of points corresponding to Hegu or Zusanli in man could be recorded from the head of the caudate nucleus in the rabbit, the center of response being in the dorsal part of the nucleus. In testing 110 spontaneously active caudate units recorded by micro- and multimicropipettes, 35 were found activated, 43 depressed and 32 not significantly affected. Of 50 units tested by microiontophoresis, 39 were found to be sensitive to acetylcholine (ACh), and most ACh-sensitive units showed response to electric needling. Of 77 units tested by sertonin (5HT), 27 were found sensitive and most 5-HT-sensitive units showed response to needling. In a few experiments dopamine (DA) sensitive units were also found to be responsive to electric needling. These results indicate that the afferent impulses arising from needling points can reach the head of the caudate nucleus and modulate the activity of ACh-, 5-HT and DA-sensitive neurons.
Clinical observations showed that during electric needling or caudate stimulation to relieve intractable pain, ACh content in the cerebrospinal fluid of the lateral ventricles was increased as analgesia was brought on. ACh content in the perfusates of the lateral ventricles increased simultaneously with the elevation of pain threshold when rabbits were needled, exhibiting a significant association between them. The microinjection of cholinergic blocker-scopolamine into the caudate nucleus of the animals reduced the pain threshold raising effect of needling, showing a block of various degrees. A cholinergic mechanism may thus possibly take an active part in acupuncture analgesia.
With techniques of push-pull perfusion and competitive protein binding analysis of 3',5'-adenosine monophosphate (cAMP), it was found that the cAMP level in caudate perfusates decreased simultaneously with the elevation of pain threshold during electric needling. This effect of needling could be reversed by intravenous adminstration of morphine antagonist-naloxone, suggesting that intracaudate endorphins may be related to acupuncture analgesia. The role and the correlation of caudate transmitter systems in acupuncture analgesia need to be further looked into.
The analgesic effect produced by caudate stimulation could be blocked partially by naloxone administrated either intravenously or by microinjection into the central grey. The results suggest that the stimulation produced analgesia may result, in part, from the release of endorphins onto the opiate binding sites in areas such as the central grey.
Thus, it can be assumed that one of the important CNS links in acupuncture analgesia is the modulation of neuronal activity and the activation of cholinergic and endorphin system by afferent impulses from needling points reaching the caudate nucleus.
Morphological studies with retrograde horseredish peroxidase method and Nauta's degeneration technique revealed reciprocal interconnections between the caudate and the medial thalamus; the caudate and the nucleus of raphe; and the caudate and the substantia nigra. The possible functional connections involved are to be further explored.
He Lianfang, Xu Shaofen (Research Department of Acupuncture Analgesia, Shanghai First Medical College)
Jiang Chengchuan (Huashan Hospital, Shanghai First Medical College)
This paper gives a short account of investigations made on the role of the caudate nucleus in acupuncture analgesia.
Electrophoresis of potassium ion to the skin of the rabbit's ear, served as the noxious stimulus. The minimal electric current in mA that produced the defence reaction of the head and limbs was taken as the pain threshold. It was found that the pain threshold rose significantly when the dorsal part of the head of the caudate nucleus was stimulated through chronically implanted electrodes. In clinical observations it was found that caudate stimulation brought forth alleviation of intractable pain of the patients caused by late malignancies. The characteristics of analgesia produced by caudate stimulation, such as pain relief after certain period of induction, after-effect after cessation of stimulation, calmness and wide spread analgesic effect without clear segmental topography were similiar to those of acupuncture analgesia by needling distal points. Further study in rabbits demonstrated that caudate stimulation was able to enhance the analgesic effect of electric needling, while caudate lesion resulted in attenuation of it.
Potentials evoked by electrostimulation of points corresponding to Hegu or Zusanli in man could be recorded from the head of the caudate nucleus in the rabbit, the center of response being in the dorsal part of the nucleus. In testing 110 spontaneously active caudate units recorded by micro- and multimicropipettes, 35 were found activated, 43 depressed and 32 not significantly affected. Of 50 units tested by microiontophoresis, 39 were found to be sensitive to acetylcholine (ACh), and most ACh-sensitive units showed response to electric needling. Of 77 units tested by sertonin (5HT), 27 were found sensitive and most 5-HT-sensitive units showed response to needling. In a few experiments dopamine (DA) sensitive units were also found to be responsive to electric needling. These results indicate that the afferent impulses arising from needling points can reach the head of the caudate nucleus and modulate the activity of ACh-, 5-HT and DA-sensitive neurons.
Clinical observations showed that during electric needling or caudate stimulation to relieve intractable pain, ACh content in the cerebrospinal fluid of the lateral ventricles was increased as analgesia was brought on. ACh content in the perfusates of the lateral ventricles increased simultaneously with the elevation of pain threshold when rabbits were needled, exhibiting a significant association between them. The microinjection of cholinergic blocker-scopolamine into the caudate nucleus of the animals reduced the pain threshold raising effect of needling, showing a block of various degrees. A cholinergic mechanism may thus possibly take an active part in acupuncture analgesia.
With techniques of push-pull perfusion and competitive protein binding analysis of 3',5'-adenosine monophosphate (cAMP), it was found that the cAMP level in caudate perfusates decreased simultaneously with the elevation of pain threshold during electric needling. This effect of needling could be reversed by intravenous adminstration of morphine antagonist-naloxone, suggesting that intracaudate endorphins may be related to acupuncture analgesia. The role and the correlation of caudate transmitter systems in acupuncture analgesia need to be further looked into.
The analgesic effect produced by caudate stimulation could be blocked partially by naloxone administrated either intravenously or by microinjection into the central grey. The results suggest that the stimulation produced analgesia may result, in part, from the release of endorphins onto the opiate binding sites in areas such as the central grey.
Thus, it can be assumed that one of the important CNS links in acupuncture analgesia is the modulation of neuronal activity and the activation of cholinergic and endorphin system by afferent impulses from needling points reaching the caudate nucleus.
Morphological studies with retrograde horseredish peroxidase method and Nauta's degeneration technique revealed reciprocal interconnections between the caudate and the medial thalamus; the caudate and the nucleus of raphe; and the caudate and the substantia nigra. The possible functional connections involved are to be further explored.
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