Pinyin name y m n Jin she
Alias neck swollen snake (Xue Deyu's systematic zoology), bat snake, five poisonous snakes, flat-headed wind, pipa snake (vertebrate taxonomy), blowing snake, blowing turtle, rice shovel head, rice spoon head and wannake (Guangxi annals of traditional Chinese medicine).
The source is the whole body of cobra, an animal of Cobra family. Captured before and after beginning of winter. After catching, laparotomy, take out internal organs and teeth, and dry them.
Original shape
The total length is about 120 cm. The head is not very big. The ribs between the necks can move, which makes the neck suddenly expand. The width of snout scale is 1/2 times that of high scale. The scales between the nose and eyes are not connected. Cheek scales are gone. There are 7 scales on the upper lip, and the third and fourth scales are in the eyes. The lower lip is 8 scales. Nose scales are divided into two parts, with nostrils in the middle. Immediate 1 scale; 2 ~ 3 pieces of posterior scales. Body scales are smooth and inclined; There are 24 ~ 27 rows of scales in the neck, 19 ~ 2 1 row in the middle of the body and 13 ~ 15 row in the front of the anus. Abdominal scale 164 ~ 178, anal scale 2 points, tail scale 41~ 5/pair. There are many variations in various colors and patterns. Typically, there are white or yellowish glasses-like markings on the back of the neck; The colors of the back are brown, dark brown, grayish black to dark black, etc. There are 15 ~ 16 narrow white or yellowish color rings on the back and tail. The ventral surface is gray or gray-black, which may be mixed with tiny black spots.
Habitat in plains and hilly areas, mostly near villages. Every night. Prey on frogs, fish, lizards, scorpions, snakes, mice and birds. When angry, the front of the body stands up, the neck expands and makes a sound. It has strong neurotoxicity.
Habitat distribution in Zhejiang, Fujian, Taiwan Province, Hunan, Jiangxi, Guangdong, Guangxi, Yunnan and other places.
The chemical composition of cobra venom is mainly neurotoxic and has hemolytic effect. In the early years, a crystalline snake venom component, rattlesnake toxin, was isolated, which has neurotoxic and hemolytic effects. Its neurotoxic part has been separated and purified, and it is a kind of protein with very small molecular weight. Sedimentation coefficient 1.4S, molecular weight 1 1000, relatively heat resistant. Cysteine in the molecule is bound by -S-S-. In addition, it is reported that the low molecular weight and high toxicity component (lethal dose to mice is 0.03 mg/kg) and a heat-resistant component (100℃ for 30 minutes and 120℃ for 30 minutes) may be this kind of cobra venom. The hemolysin in snake venom was proved to be lecithin A after purification. Snake venom also contains cytotoxic and cardiotoxic components (1 mg can produce necrosis with a diameter of 12 ~ 23 mm), cobra factor (an activating factor of complement C _ 3 bypass in serum), anticoagulant factors, and various enzymes (such as cholinesterase and ribonuclease).
pharmacological action
Toxicity of 1 to nervous system
Naja naja atra venom is a mixed poison which is mainly neurotoxic to human beings or animals. Its effect on nervous system is extensive and complex, and it often has a two-way effect, that is, it shows excitement or inhibition due to different doses and different sensitivities of individual animals or nervous system. The first is respiratory paralysis, which is the main cause of death. When breathing stops, the heartbeat continues for several minutes; If animals are given artificial respiration, the heartbeat can last for more than 1 ~ 2 hours. The cause of respiratory paralysis, crude snake venom may directly act on the respiratory center; The purified neurotoxin is peripheral, and the latter can be divided into three types according to different action principles: the first one is cobra neurotoxin and bungarotoxin A, whose action principle is the same as that of curare, that is, blocking the action of acetylcholine on the receptor on the motor endplate; The second is bungarus multicinctus toxin B, which acts on presynaptic motor nerve endings. The third category is cobra venom, which has the dual functions of the above two categories. Snake venom also has significant and extensive effects on autonomic nervous system, especially on chemoreceptors in carotid sinus. In carotid sinus perfusion test, low concentration snake venom can cause short-term respiratory excitement, then long-term inhibition, and can block acetylcholine response; Higher concentration can also block the reaction of potassium cyanide. This inhibition may play an important role in the cause of respiratory depression caused by snake venom poisoning. It has a strong excitatory effect on cholinergic receptors in adrenal medulla, which leads to a large amount of adrenaline secretion, which may be closely related to the increase of blood pressure, body temperature and blood sugar seen in clinic. The effect on ganglia is very weak. At high concentration, it can paralyze sensory nerve endings (numbness at the bite) and reduce or block the impulse conduction of nerve trunk. It can also increase the tension of isolated intestinal muscles and inhibit the isolated heart, indicating that snake venom also has some influence on muscarinic receptors. In the experiment of acetylcholine inclusion body synthesis, snake venom can inhibit choline acetylase, play a toxic role in the central nervous system, and block the response of frog rectus abdominis to acetylcholine, which is more than 2 times stronger than that of curculine chloride, and neostigmine can eliminate this effect.
2 Toxicity to circulatory system
Although respiratory paralysis is the first cause of death caused by cobra bite, most patients have myocardial damage and myocarditis before mild poisoning or respiratory depression, and patients with severe cobra bite poisoning have severe shock even before respiratory depression. Therefore, the poisoning of circulatory system is also an important factor of poisoning death, which can not be ignored. After the dog is injected with snake venom, the change of blood pressure can be roughly divided into three stages: the early stage-the rapid drop of blood pressure may be due to the formation of lysolecithin enzyme after phospholipase contained in snake venom enters the body, which leads to the rupture of tissue cells and the release of histamine, bradykinin, 5- hydroxytryptamine and adenosine. The release of a large amount of histamine makes pulmonary blood vessels contract, pulmonary artery pressure increase and pulmonary circulation resistance increase. In addition, histamine and bradykinin make capillaries dilate, the circulating blood volume is relatively insufficient, and the cardiac output is reduced. Snake venom accelerates the contraction of the heart in the early stage, which may be a compensation rather than a real cardiotonic effect. As for the direct excitatory effect (so-called digitalis-like effect) on isolated rabbit hearts and frog hearts, it is estimated that it has little significance in the whole situation. Mid-term-due to the anti-injury effect of the body, blood pressure gradually rises, and the respiratory and circulatory functions are in a relatively stable state. Late stage-respiratory depression, gradually turning into paralysis. Due to lack of oxygen, blood pressure often rises briefly. Under artificial respiration, myocardial contractility gradually weakened, heart rate slowed down, blood pressure continued to drop, arrhythmia appeared, and heart failure died. The cause of heart failure lies in the direct toxicity of snake venom to the heart. In the early stage of ECG, myocardial damage such as ST segment decline, flat or inverted T wave, prolonged QT interval and low voltage of R wave may occur, and in the late stage, serious arrhythmia such as atrial or ventricular premature beats, bundle branch block, ventricular paroxysmal tachycardia, ventricular rhythm or ventricular arrest may also occur. Pathological sections showed pathological changes of acute interstitial myocarditis, such as extensive myocardial turbidity, focal necrosis and subendocardial hemorrhage. Cobra venom dilates coronary vessels. The pure cardiotoxin isolated from cobra venom is a strongly alkaline polypeptide with high content, accounting for 25-40% of the dry weight of snake venom. It is extremely toxic to mammals and heart, but its lethal performance is only neurotoxic 1/20. Its main function is to depolarize the cell membrane and make the heart stop beating during systole.
3 the role of enzymes
Snake venom itself contains many enzymes, which will have a serious toxic effect on the body. Lecithinase is important, which can cause hemolysis and histamine release, invade capillary wall cells, cause pulmonary hemorrhage and ventricular fibrillation to tense contraction, and directly harm the nervous system (respiratory depression, coma). Protein lyase can damage the blood vessel wall, causing severe bleeding, tissue destruction and even bone tissue necrosis. At the same time, histamine and other substances are released, which can affect nerve function. Phosphatase and phosphodiesterase can hydrolyze adenosine triphosphate in the body, leading to its deficiency and so on. In addition, snake venom can also inhibit the activity of some important enzyme systems in the body.
4. Effect on blood
The red blood cells, hemoglobin and hematocrit of dogs and rabbits killed by cobra poisoning have no obvious changes, indicating that there is no blood concentration. Cobra venom can prolong the coagulation time of experimental animals (rabbits), and the coagulation time is obviously prolonged when snake venom is added in vitro, which can explain the bleeding tendency of patients bitten by snakes. For the whole animal, cobra venom can increase the brittleness of its red blood cells, but it does not cause hemolysis. It does not produce oxygen-fixing hemoglobin. It can increase the blood sugar of dogs, cats, rabbits and mice, which may be related to the release of adrenaline, but it can reduce the blood sugar of rats. There is no constant effect on the total number and fraction of white blood cells in animals. Clinically, some cases seem to have eosinophilia. In the glass dish, the hemolytic concentration of cobra venom is 0.00000000 1 (rabbit) or 0.000000001(dog).
Effect of 5 on endocrine
Poisoning by snake venom can cause significant changes in adrenal cortex. For example, taking the lethal dose of mice as an index, all kinds of adrenocortical preparations can effectively improve the tolerance of animals to cobra venom, while the animals with adrenal glands removed are significantly reduced. Corticosteroid supplementation can improve tolerance to normal animal level, chlorpheniramine can further improve tolerance, and the lethal dose of half can be doubled. Therefore, adrenal cortical failure may be one of the factors leading to death from snake venom poisoning. Corticosteroids and antihistamines can be used for treatment. Activation of adrenal cortex by cobra venom may also be one of the pharmacological mechanisms of treating some diseases with a small amount of cobra venom. Cobra venom also has obvious inhibitory effect on thyroid function, mainly inhibiting its iodine absorption function and thyroxine production process. Using I 13 1, the iodine absorption rate, iodine utilization rate, inorganic iodine content and average dry weight of thyroid gland in snake venom group were lower than those in control group. In the preliminary experiment with Warburg direct manometry, it was proved that cobra venom (added to a reaction bottle or injected into animals to cause severe poisoning) had no obvious effect on the oxygen consumption of rabbit heart, liver and medulla oblongata, that is, it did not inhibit cell respiration.
The taste is sweet and salty, and the temperature is poisonous.
Meridian enters liver and kidney.
Function is mainly used to dredge meridians, dispel wind and remove dampness. Treat rheumatic joint pain and beriberi. (Sex and taste are listed in Guangxi Journal of Traditional Chinese Medicine)
Usage and dosage: soaked in wine (three catties of wine soaked in half a catty of snake).
Clinical application of snake venom has analgesic effect. The analgesic effect of 0. 188 mg/kg on rats is 3 ~ 4 times that of morphine (1 mg/kg), and it does not produce tolerance and habituation. Can effectively treat neuritis, malignant tumor, cardiovascular disease, neuralgia and pain caused by nerve leprosy. It also has certain curative effect on some nervous system diseases such as Parkinson's syndrome.
Excerpt from * dictionary