Muscarinic agonists bethanechol

A. Atropine has little effect on blood pressure in the absence of a circulating muscarinic agonist because the muscarinic receptors on endothelial cells do not receive synaptic input. Therefore, the blood pressure of a healthy patient will not change with treatment with atropine. In contrast, patients being treated with an AQiE inhibitor may have slightly elevated plasma ACh levels, and patients being treated with bethanechol may be hypotensive because of its direct actions on the muscarinic receptors on endothelial cells. 

Acetylcholine acts at two different types of cholinergic receptors [see (1) and (2) in Fig. 2.5]. Muscarinic receptors bind ACh as well as other agonists (muscarine, pilocarpine, bethanechol) and antagonists (atropine, scopolamine). There are at least five different types of muscarinic receptors (M1-M5). All have slow response times. They are coupled to G proteins and a variety of second messenger systems. When activated, the final effect can be to open or close channels for K, Ca ", or CL (Bonner, 1989). Nicotinic receptors are less abundant than the muscarinic type in the CNS. They bind ACh as well as agonists such as nicotine or an-... 

Bethanechol Muscarinic agonist t negligible effect at nicotinic receptors Activates Mi through M3 receptors in all peripheral tissues causes increased secretion, smooth muscle contraction (except vascular smooth muscle relaxes), and changes in heart rate Postoperative and neurogenic ileus and urinary retention Oral and parenteral, duration 30 min does not enter central nervous system (CNS) Toxicity Excessive parasympathomimetic effects, especially bronchospasm in asthmatics Interactions Additive with other parasympathomimetics... 

Bethanechol and carbachol are synthetic muscarine agonists which are fairly persistent in the nervous system because they are not susceptible to breakdown by acetylcholineesterase. 

All muscarinic agonists can stimulate GI smooth muscle, increasing tone and motility large doses will cause spasm and tenesmus. Unlike methacholine, carbachol, bethanechol, and pilocarpine stimulate the GI tract without significant cardiovascular effects. 

Direct-acting drugs Muscarinic agonists Acetyichoiine Muscarine, carbachol, bethanechol, piiocarpine... 

This same chemical logic was extended to methacholine and led to synthesis of its carbamate ester, bethanechol, an orally effective potent muscarinic agonist with almost no nicotinic activity at therapeutic doses. Muscarinic receptors exhibit stereoselectivity tor the two optical isomers of bethanechol, and similar to methacholine, the S-(+)-enantiomer exhibits greater binding affinity at muscarinic receptors than the R-(-)-enantiomer in isolated receptor preparations. 

The male client diagnosed with urinary retention is receiving bethanechol (Urecholine), a muscarinic agonist, medication. Which intervention should the nurse implement ... 

The most typical muscarinic agonist is methacholine 12.68) L-acetyl-/S-methylcholine. This simple molecule, which differs from that of acetylcholine only in possessing one extra methyl-group, has the full muscarinic action of that neurotransmitter, but none of the latter s nicotinic action. Interestingly, it is more than 200 times as active as its D-enantiomer (Ellenbroek and Van Rossum, 1960). In human medicine, methacholine is mainly used to overcome postoperative retention of the bowels. Bethanechol 12.69), constructed as a hybrid of methacholine and carbachol (2.11), has an almost purely muscarinic action and is similarly used in the clinic. The great advantage of these drugs over acetylcholine is that they are not quickly hydrolysed by acetylcholinesterase. 

Muscarinic receptor agonists, such as carbachol and bethanechol, can improve intestinal motility, e.g. in the post operative state. Both drugs act with some... 

Methacholine, bethanechol, and pilocarpine are selective agonists of muscarinic receptors, whereas carbachol and ACh can activate both muscarinic and nicotinic receptors. However, at usual therapeutic doses, the effects of carbachol and ACh are entirely due to the activation of muscarinic receptors. This apparent preference for muscarinic receptors can be attributed to the greater accessibility and abundance of these cholinoreceptors compared with the nicotinic receptors. 

Carbachol Nonselective muscarinic and nicotinic agonist otherwise similar to bethanechol used topically almost exclusively for glaucoma ... 

The peptides listed here are not associated with marked increases in gastrointestinal motility. Bethanechol, a muscarinic choUnoceptor agonist, is an effective stimulant of the gut. The answer is (B). 

Carbachol and bethanechol are both parasympathomimetic compounds, which mimic the action of acetylcholine to stimulate muscarinic receptors in the body. Thus, these compounds are classified as chlolinergic agonists. Carbachol is primarily used for ophthalmic applications such as solutions used for glaucoma treatment or ophthalmic surgery. It constricts the iris and ciliary body resulting in a reduction of intraocular pressure in patients with glaucoma Because... 

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