Muscarinic receptors anesthetics

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... 

Oyasu H, Yamamoto T, Sato N et al. (1994) Urinary bladder-selective action of the new antimuscarinic compound vamicamide. Arzneim Forsch/Drug Res 44 1242-1249 Peterson JS, Hanson RC, Noronha-Blob L (1989) In vivo cystometrogram studies in urethane-anesthetized and conscious guinea pigs. J Pharmacol Meth 21 231-241 Pietra C, Poggesi E, Angelico P et al. (1990) Effects of some antidepressants on the volume-induced reflex contractions of the rat urinary bladder lack of correlation with muscarinic receptors activity. Pharmacol Res 22 421-432 Postius S, Szelenyi I (1983) In vivo rat bladder a new model to screen spasmolytic compounds. J Pharmacol Meth 9 53-61... 

A number of the antihistamines, particularly the phenothi-azines and aminoalkyl ethers, have antiemetic actions and thus may be u.seful in the treatment of nausea, vomiting, and motion sickness. Also, those agents that produce pronounced. sedation have application as nonpiescription sleeping aids." - "Several of the phenothiazines have limited u.se in Parkinson-like syndromes as a result of their ability to block central muscarinic receptors." -And. a number of antihistamines, including promethazine, pyrilamine. tri-pelennamine and diphenhydramine, display local anesthetic activity that may be therapeutically useful. ... 

The first-generation H receptor antagonists have many actions in addition to blockade of the actions of histamine. The large number of these actions probably results from the similarity of the general structure (Figure 16-1) to the structure of drugs that have effects at muscarinic cholinoceptor, a adrenoceptor, serotonin, and local anesthetic receptor sites. Some of these actions are of therapeutic value and some are undesirable. 

Succinylcholine Agonist at nicotinic acetylcholine (ACh) receptors, especially at neuromuscular junctions depolarizes may stimulate ganglionic nicotinic ACh and cardiac muscarinic ACh receptors Initial depolarization causes transient contractions, followed by prolonged flaccid paralysis depolarization is then followed by repolarization that is also accompanied by paralysis Placement of tracheal tube at start of anesthetic procedure t rarely, control of muscle contractions in status epilepticus Rapid metabolism by plasma cholinesterase normal duration, 5 min Toxicities Arrhythmias hyperkalemia transient increased intraabdominal, intraocular pressure postoperative muscle pain... 

Atropine blocks muscarinic cholinergic receptor competitively and has a large spectrum of clinical applications. Atropine acts as a parasympatholytic on parasymphathetically innerved organs. Therefore, the possible applications of atropine are as a general anesthetic and include its pure form or as a component. Brucine and other snake compounds interact with muscarinic acetylcholine receptors, and they are used in several types of clinical experiments, especially in autoradiography of the hippocampus in Alzheimer patients. ... 

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