Crotalus is a genus of venomous pit vipers

Crotalus is a genus of venomous pit vipers in the family Viperidae, known as rattlesnakes or rattlers. Snake venom is a liquid secreted by venomous snakes from venom glands. The main component is toxic protein, which accounts for about 90% to 95% of dry weight. There are about 20 kinds of enzymes and toxins. In addition, it also contains some small molecule peptides, amino acids, carbohydrates, lipids, nucleosides, biological amines and metal ions. The composition of snake venom is very complex, and the toxicity, pharmacology and toxicological effects of different snake venoms have their own characteristics.

Snake venom is characterized by its complex composition. Different snake species, subspecies, and even the venom secreted by the same snake in different seasons still have certain differences in toxic components. Snake venom is separated and purified, and it is known that there are neurotoxins, cardiotoxins, coagulation toxins, hemorrhage toxins and enzymes as the main components. In addition, it also contains some small molecule peptides, amino acids, carbohydrates, lipids, nucleosides, biological amines and metal ions; some of them have biological activity or have a certain relationship with biological activity. After the snake venom is purified, its toxic components can be 5-20 times greater than the crude venom, and the toxic components are also different. 

Physical and chemical properties

Snake venom is a viscous, transparent or light yellow liquid. It is a mixture of a variety of toxic proteins, enzymes and peptides. It has a water content of about 65-80%. It has a special fishy smell. It is easy to foam and can be destroyed by heating. It becomes decayed and inactivated. The fresh snake venom in the refrigerator will partially lose its virulence. After being dried in a vacuum and low temperature, the original venom can be preserved for decades. Snake venom has the common characteristics of protein and polypeptide, wherever there is strong acid and alkali. , Oxidants, reducing agents, and proteolytic enzymes can make it deteriorate and destroy. 

Toxic ingredients and toxicology

The biological function of snake venom is mainly to help snakes eat and digest food. As far as its toxic components are mainly neurotoxins, cardiotoxins, cytotoxins, hemorrhagic toxins, procoagulant and anticoagulant components, and some enzymes, how much each contains None, varies with snake species.

1. Neurotoxin:

Divided into two types according to the action site and action mode:

One is to act on the post-synaptic membrane at the junction of the motor nerve and the skeletal muscle, and combine with the cholinergic receptor of the posterior membrane, so that the acetylcholine released by the motor nerve terminal does not work on the receptor, which leads to skeletal muscle relaxation , Called post-synaptic neurotoxin, its action characteristics are like curare, also known as pseudo-curar-like neurotoxin. 

The other is the presynaptic membrane that acts on the nerve-muscle junction to inhibit the release of acetylcholine in the presynaptic membrane. 

2. Blood circulation poison:

There are many types of blood circulation toxins, with complex components, mainly in the cardiovascular and blood systems, which produce multiple toxic effects.

(1). Membrane toxin: Membrane toxin is a strong basic protein, which is less toxic than neurotoxin and can damage the structure and function of cardiomyocytes. After a snake injury, as the concentration of snake venom in the blood circulation increases, it may turn to inhibition after a short period of excitement, heartbeat disorder, ventricular fibrillation, and even myocardial necrosis, leading to heart failure and death. If PLA2 (phospholipase A2) is present, the toxin can hemolyze a lot, which will accelerate the death of shocked animals.

(2). Cytotoxin: Acting on the cell membrane, causing the membrane structure to change to release cell contents, and it can also directly dissolve the red blood cells of certain animals. 

(3). Hemorrhagic toxins: cause animal edema, bleeding and tissue necrosis. The local effect of this toxin is rapid, which can increase local permeability, produce extensive blood extravasation, and cause bleeding in multiple organs.

3. Enzymes:

(1) Proteolytic enzymes: most proteolytic enzymes can coagulate fibrinogen, and proteolytic enzymes can damage blood vessel walls and cause severe bleeding, tissue destruction, and even deep bones, while releasing histamine, histamine and brady. Peptides can cause blood pressure to drop sharply to shock levels. It also increases the permeability of nerve cells and affects nerve function. 

(2) Phospholipase A2 (PLA2): has presynaptic neurotoxicity, myolysis, cardiotoxicity, hemolysis, hemorrhage, procoagulation, anticoagulation, warming and inhibition of platelet aggregation, blood pressure reduction, Edema effect and so on. 

A high school student in China raised a pit viper as a pet. He found that the snake he had recently had a poor appetite. After questioning the hobby circle, he suspected that it had oral inflammation. He decided to apply medicine to the snake. Unexpectedly, when he opened the snake’s mouth, he was bitten by the snake. , Urgent medical treatment.

According to a comprehensive Chinese media report, a high school student in Hangzhou, China raised a cauliflower primordial spearhead as a pet. This snake is very venomous, but it is still popular among pet snake lovers. After buying it 4 months ago, the teenager kept the snake in peace On the balcony of his home, he recently found that the snake's activity was reduced and the appetite was poor. After consulting in the hobby circle, he suspected that the snake had oral inflammation. Netizens suggested that it can be cured by applying medicine for a few days.

According to the experience of netizens, the teenager opened the snake’s mouth and applied the medicine for him. The first few times went well, resulting in a decrease in his vigilance. One time when he applied the medicine, he slackened and did not wear protective gloves. As a result, he was in the process of changing the medicine. Suddenly he bit his master's thumb.

Fortunately, this high school student usually puts anti-snake venom medicine at home. After taking it for the first time, he was immediately sent to the doctor for emergency treatment. After the serum was injected, he was out of danger. The doctor said that the toxicity of the cauliflower protospermum is relatively strong. If the bite is not dealt with in time, multiple organ failure symptoms will usually appear within 24 hours, which may be life-threatening in severe cases.

The teenager confessed that he usually wears special protective gloves when feeding and applying medicine. At this time, he was negligent and applied medicine to the snake without wearing the gloves, and the danger of being kissed by the snake appeared.