Cholinergic agents/agonists

Nicotinic Receptor Agonists. There has been significant activity in the development of muscarinic cholinergic receptor agonists for dementia. In addition, agents that interact with nicotinic cholinergic receptors may also have therapeutic value. Nicotinic receptors have been reported to be... 

Relief from pain. Selected cholinergic agents have been found that display antinociceptive (analgesic) effects grossly similar to those of morphine. Most of these are nicotinic receptor agonists, but a modest number of muscarinic agonists have been found that also display antinociceptive effects. 

Far more intrinsic factor is secreted than is needed to bind and assimilate dietary cobalamin. Thus, in a 60-minute period, the stimulated human stomach secretes enough intrinsic factor to bind all cobalamin ingested in a 24-hour period. Intrinsic factor secretion appears to be stimulated by all agents that stimulate acid secretion. It is thus secreted under stimulation by histamine, pentagastrin, and cholinergic agents and is similarly inhibited by cimetidine. The pattern of intrinsic factor secretion, however, differs from that of acid secretion. Exposure to an agonist results in a rapid stimulation, with peak levels of intrinsic factor within 15 to 30 minutes, whereas acid increases over a far slower period. When acid secretion is at a maximum level, intrinsic factor secretion has returned to control levels. 

Figure 13.3. An overview of the chemical events at a cholinergic synapse and agents commonly used to alter cholinergic transmission acetyl CoA, acetyl coenzyme A Ch, choline. Nicotine and scopolamine bind to nicotinic and muscarinic receptors, respectively (nicotine is an agonist while scopolamine is an antagonist). Most anti-Alzheimer drugs inhibit the action of the enzyme cholinesterase.

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