Cholinergic-receptor-blocking agents

Atropine, hyoscyamine, and hyoscine are cholinergic receptor blocking agents. Autonomic drugs have extensive clinical applications. They have the following uses ... 

Cyproheptadine, a serotonin and histamine,-receptor and muscarinic cholinergic receptor-blocking agent, has been used in the treatment of the postgastrectomy dumping syndrome and the intestinal hypermotility seen with carcinoids. 

Calcium-channel blockers for the treatment of hypertension Calcium products Cephalosporins Cerebroactive medications Chlamydial infections treatment of Cholinergic drugs uses in medicine Cholinergic-receptor-blocking agents uses of Cirrhosis treatment of Congestive heart failure treatment of Constipation drug-induced Corticosteroids uses for Crohn s disease treatment of Cytokines their actions... 

Most antipsychotics and especially the piperazines and the butyrophenones can cause extrapyra-midal symptoms. Blockade of dopamine receptors mainly in the corpus striatum is held responsible for these extrapyramidal effects. They may become manifest as a variety of clinical symptoms and it should be noted that within 24 8 hours after the beginning of treatment acute dystonic reactions like torticollis, facial grimacing and opisthotonos may occur. Parkinsonism-like symptoms such as bradyki-nesia, rigidity and tremor occur after weeks or months of therapy and are more common in the elderly. Motor restlessness, i.e. akathisia, also mostly occurs not before weeks or months after starting therapy. The tendency of an antipsychotic agent to produce extrapyramidal symptoms appears to be inversely related to its ability to block cholinergic receptors. 

Mecfianism of Action An anticholinergic agent that blocks central cholinergic receptors (aids in balancing cholinergic and dopaminergic act ivity) Tiicrapc tic Effect Decreases salivation, relaxes smooth muscle. 

The answer is d. (Hardman, pp 192-193.) Nicotine is a depolarizing ganglionic blocking agent that initially stimulates and then blocks nicotinic muscular (NM) (skeletal muscle) and nicotinic neural (NN) (parasympathetic ganglia) cholinergic receptors. Blockade of the sympathetic division of the autonomic nervous system (ANS) results in arteriolar vasodilation, bradycardia, and hypotension. Blockade at the neuromuscu-... 

NEUROTRANSMITTERS AND THEIR RECEPTORS 4.2.5.2 Cholinergic Antagonists Neuromuscular Blocking Agents... 

FIGURE 19-2 Structures of acetylcholine and atropine. Atropine and similar agents antagonize the effects of acetylcholine by blocking muscarinic cholinergic receptors. 

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