Antagonists specific agents

The monoamine hypothesis, like the neurotrophic hypothesis, is at best incomplete. Many studies have not found an alteration in function or levels of monoamines in depressed patients. In addition, some candidate antidepressant agents under study do not act directly on the monoamine system. These include glutamate antagonists, melatonin agonists, and glucocorticoid-specific agents. Thus, monoamine function appears to be an important but not exclusive factor in the pathophysiology of depression. 

The general clinical applications of alpha and beta antagonists are presented below. Specific agents within each major group are also discussed. 

Tertiary-amine muscarinic receptor antagonists gain access to the central nervous system and are therefore the anticholinergic drugs used to treat parkinsonism and the extrapyramidal side effects of antipsychotic drugs. Specific agents used primarily for these conditions include benztropine mesylate (Cogentin) and trihexyphenidyl hydrochloride (Artane, others). 

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