Can thiệp với truyền tín hiệu trong dây thần kinh Potency các chất độc thần kinh Chất độc thần kinh là các chất hoạt tính sinh học nhất được biết đến. Một số độc tố tự nhiên từ các vi khuẩn như các độc tố botulinum (liều gây chết 50% dân số) LD50 ở chuột là 0,0003 mg / kg. Chúng ngăn chặn sự phát hành của acetylcholine chất truyền từ các dây thần kinh. Các triệu chứng bao gồm các vấn đề hô hấp, buồn nôn, tê liệt cơ bắp, khiếm thị. . | chapter six Interference with signal transduction in the nerves Potency of nerve poisons Nerve poisons are the most biologically active substances known. Some naturally occurring toxins from bacteria such as the botulinum toxins have an LD50 lethal dose in 50 of the population in mice of pg kg. They prevent the release of the transmitter substance acetylcholine from the nerve endings. Symptoms include respiratory problems nausea muscle paralysis and visual impairments. Humans and animals may become seriously ill after consumption of spoiled food that has been kept anaerobically due to growth of Clostridium botulinum. Fortunately the toxin is heat labile and is destroyed by cooking. Poisoning by sausage poison was very common in the 19th century Otto 1838 . Today poisoning by the mussel toxin saxitoxin originating from dinoflagellates of the gender Gonyaulax is more common. Saxitoxin has an LD50 of 10 pg kg in mouse. The poison blocks the sodium channels in the nerves leading to paralysis. Batrachotoxin a toxin from frog has a mice LD50 of 2 pg kg. This extremely potent nerve poison also blocks the voltage-activated sodium channels. The poison from the black widow spider is also extremely strong but is still not well characterized. Mushrooms algae green plants animal venoms and bacteria may have substantial amounts of nerve poisons. It seems that all phyla have species able to produce such nerve poisons. Many heavy metals such as lead and mercury may also harm the nervous system. It is not surprising that most insecticides are nerve poisons. They have LD50 values in mammals between 1 and 1000 mg kg. Selectivity It is evident that a typical nerve poison is selective because it only affects organisms having a nervous system . animals. The structure and functional elements of the nervous system in different animals are quite different and some selectivity between animals from different groups is expected. On the contrary various types of nerve cells .
