Pharmacology of cholinergic synapses

As we have seen [in a previous chapter], acetylcholine occurs in s niapses in both the somatic and the autonomic nervous system. The nicotinic acetylcholine receptor is found in the motor endplate of the skeletal muscle, and in both the sympathetic and the parasympathetic ganglia of the peripheral autonomic system. Muscarinic acetylcholine receptors are found at the endings of all secondary neurons within the parasympathetic part of the peripheral autonomous system. In addition, acetylcholine receptors of both types also occur in the brain. Drugs with a useful degree of selectivity for each of these targets are available and used in practical medicine. Selectivity is based on two principles  

Receptor type and subtype specificity of agonists or antagonists, and 

Exclusion by the blood brain barrier of drugs intended for peripheral action. 

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Whittaker VP, editor. The cholinergic synapse. Handbook of experimental pharmacology, vol 97. Berlin, Heidelberg Springer-Verlag 1988. 

Tucek S. Choline acetyltransferase and synthesis of acetylcholine. In Wittaker VP, ed. The Cholinergic Synapse Handbook of Experimental Pharmacology. Berlin Springer-Verlag, 1988, pp. 125-165. 

Meeter, E., 1973, The functional significance of the cholinergic synapses responsible for carbachol hypothermia in the rat, in The Pharmacology of Thermoregulation, (E. Schonbaum and P. Lomax, eds.), pp. 492-498, Karger, Basel. 

A great deal is known about ACh and the cholinergic nervous system. Detailed accounts of the physiology and pharmacology are beyond the scope of this chapter. Here, we concentrate on the essential function of ACh and cholinergic synapses from the standpoint of how transmission can be intermpted by toxic causes. 

Jane, F. et al (1991) Pharmacological treatment of Aldieimer s disease present situation and perspectives. The role of interactions between the cholinergic system and other neuromodulatory systems in learning and memory. Synapse. 7.I5M68. 

Acetylcholine mediates two different types of activity via corresponding receptors - muscarinic and nicotinic - which relate to the pharmacological activities of two natural prodncts, mnscarine and nicotine. The former type of action occurs in nerve synapses and the latter at nenromnscnlar jnnctions and peripheral ganglia. The term cholinergic is nsed for the general effects of acetylcholine. 

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