The Action of Snake Venoms on Nerve and Muscle

Abstract

Snake venoms, especially of Elapidae and Hydrophiidae, have been known for centuries to produce symptoms relevant to nervous systems in the envenomed subject. As described in detail in Chapter 24 and 25, the most characteristic symptom is the paralysis of voluntary muscle which results in respiratory failure. Neurotoxins are believed to be the causative factor of these snake venoms dismissing voluntary muscle from nervous control and, in general, are the major principle for their lethal toxicity. Although venoms of viperid and crotalid snakes cause death by their detrimental effects on the cardiovascular system, on blood coagulation, or by hemorrhage (see Chaps. 14, 15, 18), a few of these also contain neurotoxins and kill the victims in a way similar to venoms of elapid and hydrophid snakes, causing neuromuscular paralysis. Interestingly, there are some microbial toxins and venoms from other animals which also cause respiratory paralysis on intoxication. Apparently, nature has chosen this vital system as a target for the effective toxic action during evolution.