Other direct-acting cholinergic agonists Carbachol:Also known as carbamylcholine,is a synthetic cholinergic agonist acting on both muscarinic and nicotinic receptors.It is not susceptible to AChE,making it longer lasting than acetylcholine(2-5 min onset,4-8 h duration,24 h duration by intraocular administration).Used primarily for treatment of glaucoma. Bethanecol:A B-methylated carbachol,its action is selective for muscarinic receptors. Bethanechol can be administered orally or subcutaneously for treatment of urinary retention resulting from general anesthetic diabetic neuropathy of the bladder.It is also used for treating gastrointestinal atony (lack of muscular tone).Unlike carbachol and pilocarpine which are used for treating glaucoma through activation of the M3 muscarinic receptor,in vitro study showed that bethanecol does not activate the M3 receptor. Oxotremorine:Extremely potent muscarinic agonist,synthetic,enters CNS Lobeline:Plant derivative,nicotinic but with lower potency than nicotine. Dimethylphenylpiparazinium(DMPP):Potent synthetic nicotinic stimulant;selectively activate ganglionic nicotinic receptors
Oxotremorine: Extremely potent muscarinic agonist, synthetic, enters CNS Lobeline: Plant derivative, nicotinic but with lower potency than nicotine. Dimethylphenylpiparazinium (DMPP) : Potent synthetic nicotinic stimulant; selectively activate ganglionic nicotinic receptors. Other direct-acting cholinergic agonists Carbachol: Also known as carbamylcholine, is a synthetic cholinergic agonist acting on both muscarinic and nicotinic receptors. It is not susceptible to AChE, making it longer lasting than acetylcholine (2-5 min onset, 4-8 h duration, 24 h duration by intraocular administration). Used primarily for treatment of glaucoma. Bethanecol: A -methylated carbachol, its action is selective for muscarinic receptors. Bethanechol can be administered orally or subcutaneously for treatment of urinary retention resulting from general anesthetic diabetic neuropathy of the bladder. It is also used for treating gastrointestinal atony (lack of muscular tone). Unlike carbachol and pilocarpine which are used for treating glaucoma through activation of the M3 muscarinic receptor, in vitro study showed that bethanecol does not activate the M3 receptor
Indirect cholinergic agonists (cholinesterase inhibitors,anticholinesterases) Acetylcholinesterase(AChE) Bound to the basement membrane in the synaptic cleft at cholinergic synapses Also present as a soluble form in cholinergic nerve terminals;function unknown Binds Ach,forming a transient intermediate which then becomes acetylated AChE and choline;spontaneous and rapid deacylation follows,regenerating the enzyme Butyrylcholinesterase (BChE,pseudocholinesterase) Widely present,including a presence in soluble form in the plasma Not particularly associated with cholinergic synapases Broader substrate specificity than AChE;hydrolyses butyrylcholine more efficiently than acetylcholine;function remains largely unknown Together with AChE,keeps acetylcholine concentration in plasma nearly undetectable
Indirect cholinergic agonists (cholinesterase inhibitors, anticholinesterases) Acetylcholinesterase (AChE) • Bound to the basement membrane in the synaptic cleft at cholinergic synapses • Also present as a soluble form in cholinergic nerve terminals; function unknown • Binds Ach, forming a transient intermediate which then becomes acetylated AChE and choline; spontaneous and rapid deacylation follows, regenerating the enzyme Butyrylcholinesterase (BChE, pseudocholinesterase) • Widely present, including a presence in soluble form in the plasma • Not particularly associated with cholinergic synapases • Broader substrate specificity than AChE; hydrolyses butyrylcholine more efficiently than acetylcholine; function remains largely unknown • Together with AChE, keeps acetylcholine concentration in plasma nearly undetectable