Muscarinic receptors ketamine

Metabotropic G-protein linked receptors are also modulated by general anesthetics. In particular, the current produced through activation of muscarinic receptors (Ml) for acetylcholine and the serotonergic receptor 5HT2 is inhibited by halothane, isoflurane and enflurane (Lin et al., 1993 Minami et al., 1994 Durieux, 1995). Ketamine inhibits muscarinic receptors although there is no stereospecificity of inhibition (Durieux Nietgen, 1997). The S-isomer of ketamine is more potent as an anesthetic than the R-isomer (Benthuysen et al., 1989). It is thus unlikely that the Ml muscarinic receptor plays a role in... 

Ketamine appears to act similarly to phencyclidine (PCP also known as Angel Dust), which acts as an antagonist within the cationic channel of the NMDA receptor complex (36). By preventing the flow of cations through this channel, ketamine prevents neuronal activation, which normally is required for the conscious state. The analgesic activity of ketamine, however, is more likely the result of an interaction with an opioid receptor or the less-well-understood o-receptor. Other studies have suggested a possible involvement of serotonin receptors and muscarinic receptors (37). Ketamine, like PCP, has a significant potential for abuse. 

Hustveit, O. Maurset, A. Oye, 1. Interaction of the chiral forms of ketamine with opioid, phencyclidine, sigma and muscarinic receptors. Pharmacol. Toxicol. 1995, 77, 355-359. 

Schneider, P.G., de Lores Arnaiz, G.R., 2013. Ketamine prevents seizures and reverses changes in muscarinic receptor induced by bicuculline in rats. Neurochem. Int 62, 258-264. 

The mechanisms of action of phencyclidine and ketamine are complex (Gorelick Balster, 1995). The drugs are non-competitive antagonists at NMDA receptors, and also bind to associated phencyclidine/sigma opioid receptors. They also have agonist actions at dopamine receptors, complex interactions with both nicotinic and muscarinic acetylcholine receptors and poorly understood interactions with noradrenergic and serotonergic systems. These multiple actions may combine to produce delirium and psychotic reactions. 

---