The Mechanism of Nervous

He wrote three books, The Basis of Sensation (1927), The Mechanism of Nervous Action (1932), and The Physical Basis of Perception (1947), and was knighted Baron of Cambridge in 1955. He died on August 4, 1977, and is buried at Trinity College. 

The experiments so far described remove one main difficulty,—the question whether or not ACh can be metabolized at the high speed required. But there remains the other objection mentioned above, namely that the facts based on the electrical signs of nerve activity make unnecessary the assumption of a fundamental difference between conduction along axon and transmission across synapses. Although the electrical signs of nerve activity are not sufficient to explain the mechanism of nervous action, no conclurion drawn from observations with chemical or pharmacological methods should be in contradiction to that based on observations with the much more sensitive electric recording instruments. 

Health and Safety Factors. Carbonyl sulfide is dangerously poisonous, more so because it is practically odorless when pure. It is lethal to rats at 2900 ppm. Studies show an LD q (rat, ip) of 22.5 mg/kg. The mechanism of toxic action appears to iavolve breakdowa to hydrogea sulfide (36). It acts principally on the central nervous system with death resulting mainly from respiratory paralysis. Little is known regarding the health effects of subacute or chronic exposure to carbonyl sulfide a 400-p.g/m max level has been suggested until more data are available (37). Carbon oxysulfide has a reported inhalation toxicity in mice LD q (mouse) = 2900 ppm (37). 

Almost all systemic effects of methyl parathion are related to the action of this compound on the nervous system or are secondary to this primary action. It is therefore necessary to preface a description of the mechanisms of toxicity of methyl parathion with a brief discussion of the nervous system and neuro-humoral transmitters (excerpted from Lefkowitz et al. 1996). 

Eldefrawi, M.E. and Eldefrawi, A.T. (1991). Nervous-System-Based Insecticides—Describes the mechanisms of action of a wide range of neurotoxic compounds, both human-made and naturally occurring. 

Neonicotinoids are potent broad-spectrum insecticides that exhibit contact, stomach and systemic activity. Acetamiprid, imidacloprid, nitenpyram, thiamethoxam and thiacloprid are representatives of the neonicotinoid insecticides (Figure 1). The mechanism of action is similar to that of nicotine, acting on the central nervous system causing irreversible blocking of postsynaptic nicotinic acetylcholine receptors (nAChR). Neonicotinoid insecticides are often categorized as antagonists of the... 

The mechanism of diarrhea has not been clearly elucidated, but theories include a reduction in the absorptive surface along with impaired absorption owing to cellular damage, enterotoxigenic effects of a rotavirus protein, and stimulation of the enteric nervous system.43... 

Steroid hormones regulate a very extensive assembly of functions in numerous corporal tissues. Estrogens, the steroid hormones to which the majority of this chapter is dedicated, regulate from basic functions related to reproduction, the development of the skeleton, the maintenance of arterial tension, or diverse nervous functions. The molecular studies on the mechanism of action of estrogens have set the foundations that will permit us to understand how they carry out such diverse functions in such dissimilar tissues as well as how some substances that act through the estrogen signaling pathway can exercise opposite functions in different tissues. In this respect, there are five facts of particular importance that constitute the central nucleus of this revision ... 

Although cumulative effects of cyano and non-cyano pyrethroids on motor activity were reported [23], it is difficult to demonstrate the common mechanism using such a non-specific endpoint, as motor activity is an apical measure of the disruption of nervous system function [24]. 

HCN is among the most rapidly acting of all known poisons. Absorption occurs by all routes the mechanism of action is inhibition of cellular respiration. The respiratory, central nervous, and cardiovascular systems are the primary targets of an acute exposure. Information on human exposures was limited to exposures to high concentrations for short time intervals, poorly documented accidental exposures, and chronic occupational exposures. 

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