What Is Tetrodotoxin?

Tetrodotoxin, a marine toxin found in animals such as puffer fish, tadpoles, and spotted toads. Molecular formula C11H17N3O8. Colorless prismatic crystal. Unstable to heat. Insoluble in water, soluble in weak acid aqueous solution. Decomposes easily in alkaline solutions and is unstable in low pH solutions. Tetrodotoxin is a strong neurotoxin. Very low concentrations of tetrodotoxin can selectively inhibit sodium ions from passing through nerve cell membranes. Tetrodotoxin has other pharmacological effects and is a useful tool for neurophysiological and muscle physiology research. Its toxicity is 1250 times that of the highly toxic drug sodium cyanide, and only 0.48 mg can cause death. In fact, puffer fish's muscles do not contain toxins. The most toxic parts of puffer fish are the ovaries and liver, followed by the kidneys, blood, eyes, gills, and skin. The degree of puffer fish toxicity is also related to its reproductive cycle. Pufferfish carrying eggs in late spring and early summer are most toxic. This toxin can cause nerve paralysis, vomiting, chills in the limbs, and stop heartbeat and breathing.

Puffer fish, also known as bubble fish, ancient name: hóu tái, alias: also known as dolphin, bubble fish, spicy fish, called small jade spots, large jade spots, black wolf, etc. in Jiangsu and Zhejiang, and Guangdong By fish,

Methods: After the hospital admission, patients were treated with gastric lavage, catharsis, and symptomatic treatment. EEG was performed immediately, and the EEG was reviewed at 2 and 4 weeks. Place scalp electrodes according to international 10/20 system, using domestic

General information: A total of 41 patients in this group were treated from April 1993 to July 1998, including 39 males and 2 females, aged 23 to 52 years, with an average of 43.7 years. Inclusion Criteria: History of eating or eating magpie fish; numbness of upper lip, weakness of limbs, nausea, vomiting, unstable gait and other symptoms after eating, breathing difficulties, decreased blood pressure, coma and other serious causes that could not be excluded; , Brain, kidney, liver, lung and other diseases.

Results: In 41 cases of EEG, there were no abnormal cases (2.44%), and 11 cases of mild EEG abnormalities (26.83%). The main manifestations were: the basic wave frequency became slower, and 2 cases showed slower . In 4 cases, the alpha index was less than 60%; in 7 cases, the number of theta waves increased, and the theta index exceeded 20% in 7 cases. The EEG returned to normal after one month. There were 22 cases of diffuse EEG abnormalities (accounting for 53.66%). The main features were: disintegration of basic rhythm, 14 cases with index less than 20%; significantly increased number of slow activities, 9 cases with index exceeding 30%, and index exceeding 15% were in 5 cases. Most of the slow waves are diffusely and symmetrically distributed in the cerebral hemispheres on both sides. Eighteen patients returned to normal after one month, and four patients returned to normal after 4 to 6 months. There were 7 cases of focal activity on the background of paroxysmal and diffuse abnormalities of EEG (17.67%), of which 3 cases were paroxysmal rhythms with synchronous spikes, spikes, spines and slow waves, one After 2 months, 2 cases returned to normal, 4 cases recovered after 6 months, and 1 case has not recovered to normal so far (more than 5 years), and tremor appeared. In 29 cases of diffuse and paroxysmal abnormal EEG, 8 cases had intermittent frontal rhythmic activity ^[2] .

With the advancement of science, the dreaded tetrodotoxin has entered the pharmacy hall and is playing an increasingly important role in treating human diseases. Tetrodotoxin can be used medically to treat cancer. "Newborn oil" is an anticancer drug extracted from the puffer fish liver. It is used for the treatment of nasopharyngeal cancer, esophageal cancer, gastric cancer and colon cancer, with good curative effect. Blowfish can be used for pain relief. Tetrodotoxin preparations have good analgesic effects on cancer pain, pain after surgery, and pain caused by medical gastric ulcers. The benefits of using tetrodotoxin are very little (only 3 micrograms), long pain relief, and no addiction. Acupoint injection, in particular, has fast action and obvious effect, and can be used as a good substitute for morphine and dulidine, an addictive analgesic. Tetrodotoxin can also relieve asthma, antispasmodic and itching. Tetrodotoxin can treat asthma and pertussis. It is effective for treating gastrointestinal spasm and tetanus spasm. Tetrodotoxin has a strong killing effect on bacteria. The toxin extracted from the pufferfish testis has an inhibitory effect on dysentery, typhoid, staphylococcus, streptococcus, and vibrio cholerae, and can prevent influenza. At present, in the international market, the crystals of tetrodotoxin have reached 170,000 US dollars per gram. Now, aquatoxin can be artificially synthesized.

The toxin has caused widespread social discussion: TTX is one of the most toxic non-protein substances found in nature at present. Toxins mainly include tetrodotoxin and tetroic acid. It first acts on the gastrointestinal tract and can cause local irritation symptoms, and secondly Inhibition of the central and peripheral nerves occurs rapidly after entering the blood. In this group, 1 case of normal EEG may be related to very little food intake. 40 cases of abnormal EEG, accounting for 97.56%, indicate that TTX has inhibitory effect on brain wave transmission, and the abnormality of EEG is mild and severe. Diffusion anomalies are the most common, accounting for 53.66%. Some paroxysmal and diffuse anomalies have focal activities on the background, accounting for 17.07%. They appear to be slower in frequency, lower in voltage, and reduced or disappeared in alpha waves. Delta waves are dominant. In terms of appearance, half of them are persistent and some are episodic. The changes in EEG after tetrodotoxin poisoning may be that tetrodotoxin selectively blocked the network structure of the thalamus, hypothalamus and brainstem and activated the permeability of the system membrane to Na +, causing metabolic disturbances in the starting structure of the brain waves. Diffuse abnormalities of brain waves or paroxysmal abnormalities caused by supersynchronization of cortical activity. In this group, 8 cases had intermittent frontal rhythmic delta activity. The appearance of this rhythm is presumably caused by affecting the dorsal medial nucleus of the thalamus and the nucleus of the medullary plate and triggering this wave pacing point located in these structures. . The abnormal manifestations of this group of EEG are consistent with the above-mentioned pathological characteristics, but these manifestations of EEG are similar to the changes in EEG caused by other diseases, and they are not specific, so it cannot be determined solely by EEG changes. Diagnosis, but when the type of poisoning is unknown, it is an important basis to help identify the diagnosis. A total of 31 cases returned to normal after a month of follow-up EEG, 9 cases did not recover, and 8 cases recovered after half a year, suggesting that after pufferfish poisoning, the damage to the patient's brain function is reversible, but the duration is longer, and the condition becomes worse The larger the EEG changes, the longer the duration. One case has not recovered yet, and gradually appears changes such as tremor paralysis and memory loss. The performance of EEG in different stages is different, and the degree of abnormal EEG is more severe in the acute stage. With the improvement of the condition, the EEG It also gradually returned to normal and was slightly slower than the clinical recovery. Therefore, multiple EEG tracings during the course of the disease can help estimate the degree of the disease, judge the treatment effect and the outcome. EEG showed multiple paroxysmal slow waves after repeated examinations, and the general appearance of persistent or paroxysmal slow waves is one of the characteristics of subcortical damage. When the above characteristics appear in the patients with Hexi poisoning, it may indicate a poor prognosis. The changes of EEG after tetrodotoxin poisoning are not specific. EEG alone cannot be used to determine tetrodotoxin poisoning. It must be combined with clinical manifestations and other tests to have diagnostic significance. Since EEG is relatively sensitive and has a high abnormal rate, it is a convenient and reliable method for judging treatment effects and outcomes. However, the number of observations in this group is still small, and severely dying patients are not included in the observation, which may be more limited.