Oxotremorine cholinergic

Initial attempts to treat AD using direct cholinergic agonists were limited by low efficacy and side-effect issues (140—142). Thus trials using RS-86 (25), oxotremorine [70-22-4] (26), arecoline [63-75-2] (27), and pilocarpine [92-32-7] (28) to treat AD were equivocal (Eig. 5). However, the identification of multiple subtypes of muscarinic receptors has stimulated a search for subtype specific muscarinic agonists which may limit side effects while increasing efficacy. 

A crude alkaloidal fraction from the stem of Tabernaemontana pandacaqui decreased the motor activity, respiratory rate, induced ataxia, antinociception, and loss of screen grip in rats, suggesting a CNS depression. The extract brought about the prolongation of pentobarbital sleeping time and the oxotremorine-induced salivation, hence possible cholinergic effects (13). 

N-methylscopolamine (Costa et al. 1982b Schwab et al. 1983). Animals made tolerant to disulfoton were resistant to the lethal or adverse effects of cholinergic agonists, such as carbachol (Brodeur and DuBois 1964 Costa et al. 1981 Schwab and Murphy 1981) and oxotremorine (Costa et al. 1982b McPhillips 1969a), which are not hydrolyzed by acetylcholinesterase. Tissues from animals tolerant to disulfoton such as the ilea (Foley and McPhillips 1973 McPhillips 1969b McPhillips and Dar 1967) and the atria (Perrine and McPhillips 1970 Schwab et al. 1983), were resistant to the effects of carbachol and/or oxotremorine. Because the uterus and vas deferens have a relatively sparse parasympathetic innervation compared to the ileum and do not receive a steady flow of impulses via this system, these tissues were not as subsensitive to carbachol as the ileum (Foley and McPhillips 1973). Thus, acetylcholine accumulation may be a prerequisite for tolerance development. 

Other cholinergic agonists have no therapeutic use. Muscarine (4.3) is an alkaloid of the mushroom Anumita muscaria muscarone (4.9) is its semisynthetic analog. Pilocarpine (2.2) is found in the leaves of a shrub and can be used to increase salivation or sweating. Arecoline (4.10) is also an alkaloid, and occurs in the betel nut that is used as a mild euphoriant in India and Southeast Asia. Finally, oxotremorine (4.11) is a synthetic experimental agent that produces tremors and is helpful in the study of antiparkinsonian drugs. 

Tremorine (181), a synthetic compound with w/esk cholinergic activity (211,212) is metabolized to the lactam oxotremorine (182),... 

All members of a series of oxotremorine analog (184a-e), in which the pyrrolidone ring iscontracted to a j3-lactam moiety (217), demonstrated uniformly weak cholinergic effects. 

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