Types of acupuncture anesthesia for spinal acupuncture anesthesia

Nerve pathways of acupuncture analgesia

1. Peripheral afferent pathways of acupuncture signals: Acupuncture signals are transmitted to the center through the deep receptors of the acupoints and the excitement of nerve endings. Studies have shown that the types of nerve fibers excited by acupuncture include Aa, Ab, Ad, and C. It is generally believed that the strength of acupuncture that patients can accept is mainly excited by Ab and Ad fibers. Therefore, acupuncture uses weaker stimulation. To achieve the purpose of analgesia; but there are also studies showing that the introduction of type C fibers plays an important role in acupuncture analgesia. Animal experiments have found that low-intensity electroacupuncture (non-noxious) causes a small analgesic range, while high-intensity electroacupuncture (noxious stimulus) causes a large analgesic range. The strength of acupuncture excites class C fibers may be A noxious stimulus way to inhibit another noxious thorn to achieve the purpose of analgesia. However, the amount of stimulus commonly used in clinical practice is not too strong a stimulus that the patient can bear.

2. The conduction pathway of acupuncture signals in the spinal cord: After the acupuncture impulse enters the spinal cord, it mainly crosses to the contralateral ventrolateral spinal cord and upwards, which is similar to the conduction pathway of pain and temperature. This is acupuncture signal and pain The interaction of signals in the incoming process provides a morphological basis. In patients with syringomyelia, the lesion involves the anterior spinal cord or the ventrolateral cord, and the segmental pain and temperature sensation on one side disappears. Acupuncture at the corresponding acupuncture point does not cause obvious needle sensation, and the spinal dorsal tract is damaged When the time, it does not affect the generation of needle sensation. When the acupuncture signal is transmitted ascending, on the one hand, it affects the activities of the neighboring segments and the painful afferents of the adjacent segments through the segmental connections in the spinal cord, and more importantly, the ascending to reach the brainstem, diencephalon and forebrain, etc. To achieve the analgesic effect by activating the high-position center to release downward inhibitory impulses. This suppression impulse mainly descends to the dorsal horn of the spinal cord along the dorsolateral spinal cord.

3. The integration of acupuncture signals and pain signals at the level of the spinal cord: Acupuncture signals enter the spinal cord along the afferent nerves and interact with nociceptive signals from the painful area. Microelectrodes can record high-frequency continuous discharges caused by noxious stimuli in the V-layer cells of the spinal-neck tract or dorsal horn. This type of pain-sensitive cell discharge can be inhibited by electrical acupuncture stimulation of acupoints or electrical stimulation of nerve trunks. The experiment also suggests that there is a clear segmental relationship between the acupuncture information and the nociceptive stimulus information in the spinal cord. When the acupuncture site and the noxious stimulation afferent fibers reach the same or similar spinal cord segment, the inhibitory effect of acupuncture is more obvious; if the two afferent fibers reach the spinal cord segments that are far apart, then acupuncture The inhibitory effect is weaker. Clinically, zygomatic acupoints are used for forehead surgery, and Futu acupoints are used for thyroid surgery. Because the acupoints and the surgical site are in the same or similar segment, good analgesic effects have been achieved. This integration that occurs in the same or similar segments may be the physiological basis for the selection of acupuncture points in the vicinity.

4. The integration of acupuncture signals and pain signals at the brainstem level: Acupuncture signals enter the giant cell nucleus of the medulla oblongata reticular structure along the ventrolateral cord, causing unit discharge changes in the nucleus, and noxious stimulating signals can also reach the giant cell nucleus , These two signals can converge in the same nucleus and the same cell, and through interaction, the response caused by noxious stimuli is inhibited. Directly recruiting the tail part of the giant cell nucleus of the oblongata can inhibit the discharge of pain cells in the medial nucleus of the thalamus. This effect is very similar to the inhibitory effect of electroacupuncture at the "Zusanli" point. Using microelectrodes in the central gray matter of the midbrain, the central fascicle area of the medial midbrain reticular structure, and the trigeminal spinal nucleus, the long latency and long after-discharge responses to noxious stimuli can be recorded. This response can be electroporated The suppression and disappearance of acupuncture at acupoints on the limbs or related acupoints on the face occur gradually. This may be one of the physiological basis of traditional Chinese medicine for acupuncture at remote painful sites.

5. Integration of acupuncture signals and pain signals at the level of the thalamus: Using microelectrodes in the medial thalamic nucleus, especially the parafascicular nucleus and central lateral nucleus, a special form of discharge response caused by noxious stimuli is recorded. Acupuncture "Zusanli" can inhibit the discharge of such pain-sensitive cells. The inhibition process occurs slowly, and after stopping the electroacupuncture, the after-effect of the inhibition is also longer. Experiments have also suggested that the suppression of the discharge of pain-sensitive cells by this acupuncture may pass through the central mid-nucleus nucleus of the thalamus. Because 4-8 electric pulses per second stimulate the central nucleus, it can obviously inhibit the pain-sensitive cell discharge of the parafascicular nucleus cells, and sometimes the inhibition time can be as long as 5 minutes.

6. Acupuncture activates some related pain modulation structures in the brain: Many research units use electrical stimulation and damage (electrolysis, or damage with drugs, etc.) certain central structures or methods to guide the electrical activity of certain structures. The role of pricking pain. Experimental results show that damage to certain structures in the brain, such as the head of the caudate nucleus, the central middle nucleus of the thalamus, the central gray matter of the midbrain and the raphe nucleus, has no obvious effect on the pain threshold of animals, but it significantly weakens the analgesic effect of acupuncture. Acupuncture at acupoints or stimulating peripheral nerves with moderate-intensity electricity can affect the electrical activity of the cells to the nucleus.

In the research on the principle of acupuncture analgesia, people also found that acupuncture information can respond to noxious stimuli in some structures of the limbic system (such as hippocampus, cingulate gyrus, septal area, almond, preoptic area, hypothalamus, etc.) Modulation may be the physiological basis for acupuncture to weaken the emotional response to pain.

7. The integration of acupuncture signals and pain signals by the cerebral cortex: Pain and acupuncture are both sensations that enter the realm of consciousness. Theoretically, the incoming impulses that transmit these sensations will inevitably be projected to the cerebral cortex and interact there. Role and integration. Animal experiments have shown that decortexing has no effect on the analgesic effect of acupuncture in rabbits and cats, which seems to indicate that the cerebral cortex is not necessary to inhibit nociceptive reactions. Some data indicate that the analgesic effect of acupuncture on the acupuncture points of the affected limb in patients with local damage or partial resection of the sensory cortex on one side is significantly weakened. Research in this area needs to be further deepened. The downward modulating effect of the cerebral cortex on acupuncture analgesia is mainly manifested in two aspects: one is the regulation of nociceptive stimuli, such as stimulating sensorimotor area I, and its descending fibers release acetylcholine to the nociception of parafascicular nucleus of the thalamus On the other hand, the downward adjustment of the analgesic effect of acupuncture, such as electrical stimulation of sensorimotor area II, can produce analgesia through the nucleus accumbens and the nucleus raphe magnus excitement, and destroy this area, then electroacupuncture The inhibitory effect of the raphe nucleus is weakened.

The influence of the cerebral cortex on pain and analgesia is a complex adjustment effect. The elucidation of this effect requires further development of brain function research; at the same time, the research on the cerebral cortex and limbic system mechanisms of acupuncture analgesia will surely promote In-depth research on brain function.

At present, it is believed that there is a pain center in the central nervous system, a structure related to analgesia, and a modulation system for the integration and processing of various pain information. After the acupuncture information and pain information enter the spinal cord through the afferent nerves, they are processed by certain neurohumoral and pain modulation systems at all levels of the central nervous system to change the nature of pain and inhibit the sensation and response caused by painful stimulation. , So as to play an analgesic effect. 1. The role of endopioid peptides in acupuncture analgesia: Acupuncture analgesia is achieved with the participation of many transmitters or modulators. During acupuncture analgesia, the release of opioid peptides in the brain increases. Among them, endorphins and enkephalins have strong analgesic effects in the brain, and enkephalins and dynorphins have analgesic effects in the spinal cord. Acupuncture activates the endogenous opioid peptide system in the brain, which mainly exerts analgesic effects through the following three aspects: First, the endogenous opioid peptide neurons in the spinal cord release corresponding transmitters, which act on the primary sensory afferent terminal receptors and inhibit transmission. Enter the terminal to release substance P to inhibit the pain response of nociceptive neurons in the spinal cord; secondly, the opioid peptidergic neurons in the brain are excited, release transmitters, and participate in the descending inhibitory system through the complex exchange of related neurons, which inhibits The role of pain transmission; the third is that the pituitary gland-the release of endorphins into the blood also plays a role.

2. The role of classic neurotransmitters in acupuncture analgesia: When acupuncture analgesia, the synthesis and release of 5-HT in the brain increase, and the synthesis exceeds the utilization, so the content of 5-HT in the brain increases. The dorsal raphe nucleus and nucleus raphe magnus involved in analgesia in the brain are rich in 5-HTergic neurons. The axons of the former form ascending projection fibers, and the axons of the latter (that is, the descending inhibitor part) descend to the spinal cord and damage these two 3. Nucleus and projection fibers, or block with 5-HT receptor blocker 5. Road, will weaken the analgesic effect of acupuncture. Norepinephrine up and down fibers project to the brain and spinal cord respectively. Activating the adrenergic ascending projection system can counteract acupuncture analgesia; activating the noradrenergic system from the lower brainstem can strengthen acupuncture analgesia. But when acupuncture activates the dopaminergic system, it weakens or counteracts the analgesic effect of acupuncture. Acupuncture analgesia is also increased when the acetylcholinergic system in the central nervous system is activated. Transmitters and modulators interact with each other. For example, the release of endopioid peptides can achieve its analgesic effect by inhibiting the activity of noradrenergic neurons, while the dopamine system can inhibit the release of endopioid peptides to a certain extent. Sexual effect.

3. Acupuncture analgesia tolerance and cholecystokinin octapeptide (CCK-8): Acupuncture analgesia tolerance refers to a phenomenon in which the analgesic effect of acupuncture decreases after repeated acupuncture for a long time, or acupuncture for short. Acupuncture tolerance. In fact, this kind of tolerance phenomenon is common in acupuncture clinics. Han Jisheng put forward the view that "multiple electroacupuncture may cause a certain degree of tolerance" in 1979. They believe that since there are endogenous opioid peptides that mediate acupuncture analgesia in the brain, there may also be anti-opioid peptides, the opposite. After 15 years of research on this idea, they concluded that "Cholecystokinin octapeptide is an important factor in determining the effectiveness of acupuncture analgesia and morphine analgesia." The relative balance of opioid peptides and cholecystokinin octapeptide" and other conclusions, other neurotransmitters such as 5-HT and norepinephrine are also involved in the process of acupuncture tolerance.

The anti-opioid effect and mechanism of CCK-8 in the central nervous system are shown in Figure 3-4. Studies have shown that CCK-8 is a negative feedback mechanism for opioid effects, whether it is exogenously ingested opioid substances or endogenous opioid peptides, such as the accelerated release of opioid peptides caused by electrical acupuncture stimulation. Acts on CCK neurons in the central nervous system and releases them to weaken the effects of opioids. This reaction can be regarded as a negative feedback reaction of the body to the action of opioids, and it is an automatic restriction mechanism. Different individuals have different speed and intensity of CCK negative feedback. The higher the speed, the weaker the effect of electroacupuncture and morphine (called those who are ineffective in electroacupuncture analgesia or those who are ineffective in morphine analgesia), and the sedation time is shorter (it is prone to produce morphine tolerance and electroacupuncture tolerance). Research on the molecular mechanism of CCK-8 anti-opioid shows that CCK-8 has anti-opioid effects no matter in the brain or spinal cord. This effect has receptor specificity (anti-μ and anti-κ, but not anti-delta opioid analgesia) . In addition to the interaction between CCK receptors and opioid receptors on the cell membrane, they can also interact at the G protein level, and then interact in the regulation of intracellular calcium levels, that is, opioids inhibit extracellular calcium influx, while CCK— 8 IP3 can promote the release of free calcium from the intracellular calcium store, and the effects of the two are exactly opposite. Through these ways, CCK-8 has an antagonistic effect on opioid analgesia and promotes the occurrence of opioid tolerance. (1) The effect of different frequencies on the expression of central c-fos: c-fos is a kind of immediate protocarcinoma early-stage gene that exists in nerve cells, and it is caused by noxious stimulation in nerve cells related to the transmission of this information. Expressed, its product fos protein can be displayed by immunohistochemical method. Using 2Hz and 100Hz electroacupuncture, c-fos expression was used as a sign of neuron excitement, FOS protein was observed by counting FOS protein-like immunohistochemical positive cell nuclei (FIL), and the neural pathway of acupuncture analgesia was studied. The results are the same as those studied with classical physiology and neuropharmacology methods. Studies have shown that: ① 2Hz electroacupuncture causes a large amount of FIL to appear in the hypothalamic arcuate nucleus, while 100Hz electroacupuncture rarely reaches this nucleus; on the contrary, 100Hz electroacupuncture causes a large number of FIL cells to appear in the parabrachial nucleus, while 2Hz electroacupuncture does not Cause any positive reaction of the nucleus. ②Many nuclei show the specificity of frequency response. Many nuclei of the hypothalamus have a good response to 2Hz, none of them have a good response to high frequencies; and many nuclei of the brainstem network structure have a good response to high frequencies. ③The β-endorphinergic neurons in the brain are mainly concentrated in the arcuate nucleus, and a small amount are concentrated in the nucleus tractus solitarius. The fibers from the latter can go down to the spinal cord. Therefore, the β-endorphin system activated by 2Hz electroacupuncture is not only in the brain, but also It may also play an analgesic effect in the spinal cord. ④The gray matter around the midbrain aqueduct of the brainstem, the nucleus raphe magnus and the dorsal raphe nucleus play an important role in the endogenous analgesia system. Both 2Hz and 100Hz electroacupuncture activate these nuclei, and they may be shared by the two The last pass. ⑤ It is generally believed that when the stimulus intensity is fixed, the higher the frequency, the stronger the stimulus and the greater the response, but the experimental results do not support this hypothesis. Many areas of the forebrain have the same intensity response to high and low frequencies. In some nuclei of the hypothalamus and brainstem, the response of 2Hz electroacupuncture is much greater than that of 100Hz electroacupuncture, indicating that different brain regions have a preference for signals of different frequencies. It can also be called frequency response anomaly. ⑥ Some researchers attribute electroacupuncture stimulation to stress stimulation. In fact, the intensity of electroacupuncture used in the experiment is limited (no more than 3mA). Compared with the expression of immediate early genes (1EGs) caused by strong stress stimulation, electrical acupuncture The acupuncture is much weaker, and the range of the central response is much narrower. The obvious difference in brain area between 2Hz and 100Hz electroacupuncture response indicates that this is not a general stress response, but a selective specific stimulus.

(2) The effect of electroacupuncture at different frequencies on the expression of three types of opioid peptides in the central nervous system:

Researchers used in situ hybridization to observe the effects on central preenkephalin (PPE), predynorphin (PPD), and preamelanocortin (POMC) mRNA. The results showed that: ① 2Hz electroacupuncture promotes PPE expression The effect of electroacupuncture is greater than 100Hz. ②The effect of 100Hz electroacupuncture on promoting PPD expression is greater than that of 2Hz electroacupuncture. ③In general, 2Hz electroacupuncture has a wide range of effects in the brain, but it can only promote PPE expression; 100Hz electroacupuncture has a narrow range of action in the brain, mainly promoting PPD expression, but it can also promote PPE in certain brain regions. Express. ④Neither frequency of electroacupuncture could induce a significant increase in POMCmRNA.

The above studies show that the difference in the analgesic effects of electroacupuncture at different frequencies is related to the specific expression of central related genes, indicating that the application of molecular biology theories and techniques can clarify the principles of acupuncture analgesia from a deeper level. The research on the principles of acupuncture and analgesia, for the first time using modern scientific theories and methods to prove the scientific nature of acupuncture therapy in traditional Chinese medicine, which greatly promoted the modernization of acupuncture and moxibustion, making acupuncture and moxibustion gradually recognized by mainstream medicine in the world At the same time, it also promoted the research on pain physiology in our country. Therefore, the research on the principle of acupuncture analgesia has played a positive role in promoting the development of life sciences in our country.

The research on the principle of acupuncture and analgesia is the foundation of acupuncture to the world. The success of the research on the principles of acupuncture and analgesia has promoted the development of acupuncture academics: ① Traditional acupuncture techniques can be integrated with modern science. As long as the research entry point is selected, the practical experience and viewpoints of acupuncture can be discovered.

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