Lacrimation and salivation

Neurotoxins can be inhaled, ingested or absorbed. Once in the body it binds with critical neurotransmitters (acetylcholinesterase) initially causing excitation of the nervous system, conduction, then paralysis. Common signs are Diarrhea, Urination, Miosis, Broncho-spasm, Emesis, Lacrimation, and Salivation. 

When mice, rats, rabbits and guinea-pigs were exposed to a concentration of 0-88 mg./l. (i.e. 1/5000) of ethyl phosphorodifluoridate for 10 min. there was irritation of the eyes and nose with nasal discharge, lacrimation and salivation. Four minutes after exposure the mice and some of the rats developed dyspnoea, but all the animals recovered. When animals were exposed to a corresponding concentration of ethyl phosphorodi-chloridate (1-46 mg. 1. 1/5000), similar symptoms were observed and no deaths resulted. 

Signs of disulfoton toxicity, such as muscle tremors, fasciculations, lacrimation, and salivation, in animals are generally observed after a few daily doses, but begin to diminish in severity as exposure to dislllfoton continues (Bombinski and DuBois 1958). This phenomenon is known as tolerance. Tolerance appears to be a reproducible phenomenon that does not depend on the organophosphate insecticide used, the route of administration, or the animal species (Costa et al. 1982b). Several possible mechanisms have been proposed /explain this phenomenon. 

Perhaps the most prominent and well-studied class of synthetic poisons are so-called cholinesterase inhibitors. Cholinesterases are important enzymes that act on compounds involved in nerve impulse transmission - the neurotransmitters (see the later section on neurotoxicity for more details). A compound called acetylcholine is one such neurotransmitter, and its concentration at certain junctions in the nervous system, and between the nervous system and the muscles, is controlled by the enzyme acetylcholinesterase the enzyme causes its conversion, by hydrolysis, to inactive products. Any chemical that can interact with acetylcholinesterase and inhibit its enzymatic activity can cause the level of acetylcholine at these critical junctions to increase, and lead to excessive neurological stimulation at these cholinergic junctions. Typical early symptoms of cholinergic poisoning are bradycardia (slowing of heart rate), diarrhea, excessive urination, lacrimation, and salivation (all symptoms of an effect on the parasympathetic nervous system). When overstimulation occurs at the so-called neuromuscular junctions the results are tremors and, at sufficiently high doses, paralysis and death. 

Many of the physiological effects of anti-ChEs are attributable to excess neurotransmitter ACh (Taylor 1996). The precise symptoms and the time course depend on the chemicals and the localization of the receptors affected. Early symptoms of cholinergic poisoning represent stimulation of muscarinic neuro-effectors of the parasympathetic system. Effects include slowing of the heart (bradycardia), constriction of the pupil of the eye, diarrhea, urination, lacrimation, and salivation. Actions at nicotinic skeletal neuromuscular junctions (motor end plates) result in muscle fasciculation (disorganized twitching) and, at higher doses. 

Various experimental animal species were exposed to aerosols of CS generated by various methods from exposure from 5 to 90 min. The toxic signs observed in mice, rats, guinea pigs, rabbits, dogs, and monkeys were immediate, and included hyperactivity, followed by copious lacrimation, and salivation within... 

A 5-year-old child becomes ill while visiting relatives who have a farm in Arkansas. His symptoms include severe abdominal cramps with vomiting and diarrhea and profuse lacrimation and salivation. Pupillary constriction is marked. If these symptoms are due to chemical toxicity, the most likely cause is exposure to... 

The general symptoms of exposure to a nerve agent in gas form can be remembered by the acronym DUMBELS diarrhea, urination, miosis, bronchoconstric-tion (dyspnea, wheezing), emesis (vomiting), lacrimation, and salivation. Some prefer the acronym SLUDGEM salivation, lacrimation, urination, diarrhea, gastric upset, emesis, and miosis (Table S3.1). 

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