Nicotinic cholinergic antagonists

Wiley JL, LaVecchia KL, Martin BR, Damaj MI (2002) Nicotine-like discriminative stimulus effects of bupropion in rats. Exp Clin Psychopharmacol 10 129-135 Williams M, Robinson JL (1984) Binding of the nicotinic cholinergic antagonist, dihydro-beta-erythroidine, to rat brain tissue. J Neurosci 4 2906-2911 Witkin JM, Dykstra LA, Carter RB (1982) Acute tolerance to the discriminative stimulus properties of morphine. Pharmacol Biochem Behav 17 223-228 Wooters TE, Bardo MT (2007) The monoamine oxidase inhibitor phenelzine enhances the discriminative stimulus effect of nicotine in rats. Behav Pharmacol 18 601-608 Wright JM Jr, Vann RE, Gamage TE, Damaj MI, WUey JL (2006) Comparative effects of dextromethorphan and dextrorphan on nicotine discrimination in rats. Pharmacol Biochem Behav 85 507-513... 

Lippiello PM (2005) Nicotinic cholinergic antagonists A novel approach for the treatment of autism. Med Hypotheses 66 985-990. 

Spinella M, Schaeffer LA, Bodnar RJ. (1997). Ventral medullary mediation of mesencephalic morphine analgesia by muscarinic and nicotinic cholinergic receptor antagonists in rats. Analgesia. 3 119-30. 

Cholinergic antagonists have a larger therapeutie role than agonists. Again, we can distinguish drugs that selectively affect nicotinic and muscarinic receptors. 

Cholinergic Antagonists. Atropine, which is a muscarinic antagonist that in some cases also blocks the effects of nicotinic agonists, suppresses REM sleep. The effects of the muscariniclnicotinic agonist carbachol, which facilitates REM sleep, are prevented by systemic administration of atropine. Similarly, scopolamine delays the appearance of REM sleep (35). 

Although (+)-tubocurarine ((+)-TC) has been classically regarded as a competitive antagonist of nicotinic cholinergic synapses (41)... 

Chlorpyrifos at 1.5-50 pg/ml (noncytotoxic les els) arrests DNA synthesis in undifferentiated cells, having less effect on RNA synthesis and liuLe on protein synthesis effect on DNA maximal at 1 hr these effects are not blocked by atropine or mecamylamine (moscarinic and nicotinic receptor antagonists, respectively) nicotinic (cholinergic) stimulation of undifferentiated cells does not mimic chlorpyrifos chlorpyrifos (50 pg/ml for I hr) inhibits residual DNA synthesis in differentiating cultures and robustly inhibits RN.A synthesis during early differentiation. 

The cholinergic system in insects is the main target of insecticides. One class of molecules, the neonicotinoids, induces direct activation of the neuronal nicotinic acetylcholine receptors (nAChRs). In the honey bee these receptors are mainly distributed in the olfactory pathways that link sensory neurons to antennal lobes and mushroom bodies. These structures seem to play an important role in olfactory conditioning. We have previously shown that cholinergic antagonists injected in different parts of the brain impaired the formation and retrieval of olfactory memory. We then advanced the hypothesis that, through the activation of the nAChR, the neonicotinoid imidacloprid (IMI) would lead to facilitation of the memory trace. 

QAs exert a blocking effect oti the nicotinic cholinergic receptor and they are weak antagonists at the muscarinic cholinergic receptor [42], displaying similar agonistic activities as the alkaloid nicotine. Neurological (weakness, dizziness, mydriasis, anxiety, confusion, malaise, loss of coordination, visual disturbances. 

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