Acetylcholine comparative pharmacology

The primary neurotransmitter for the parasympathetic nervous system is acetylcholine, a molecule that we have just met. Now let s compare the pharmacology of these two neurotransmitters. 

Figure 6-1. Schematic diagram comparing some features of the parasympathetic and sympathetic divisions of the autonomic nervous system with the somatic motor system. Parasympathetic ganglia are not shown as discrete structures because most of them are diffusely distributed in the walls of the organs innervated. ACh, acetylcholine Epi, epinephrine NE, norepinephrine, D, dopamine N, nicotinic M, muscarinic a, p, alpha and beta adrenoceptors D, dopamine, receptors. (Reproduced, with permission, from Katzung BG [editor] Basic Clinical Pharmacology, 8th ed. McGraw-Hill, 2001.)...

In 1984, Mark E. Schroeder and Roger F. Flattum at Shell explored for nithiazine as the example, at which site these nitromethylene insecticides interact to effect their pharmacological activity. In cockroaches, the nicotinic acetylcholine receptor turned out to be the target. [140] In insects, the expression of these receptors is limited to the nervous system. There they reach a density, which is comparable only to the electric organ of the South American electric eel (Electro-phorus electricus). [ 141 ] From ligand displacement studies with nerve cell receptors of the American cockroach (Periplaneta americana), the honey-bee (Apis mellifera) and the common housefly (Musca domestica), the a-subrmit of the receptor became evident as the prime locus of interaction for neonicotinoids. 

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