Muscarine cholinergic antagonists

Boyer, J. L Martinez-Carcamo, M Monroy-Sanchez, J. A., Posadas, C., and Garcia-Sainz, J. A. (1986) Guanine nucleotide-induced positive cooperativity in muscarinic-cholinergic antagonist binding. Biochem. Biophys. Res. Commun. 134,172-177. 

FIGURE 6-43. Icon of paroxetine with muscarinic/cholinergic antagonist actions (mACH), norepinephrine reuptake inhibition (NRI), and serotonin 2D6 and 3A4 inhibition, in addition to serotonin reuptake inhibition (SRI). 

Of the anticholinergics, atropine is the drug most frequently used for the treatment of human poisoning. This muscarinic cholinergic antagonist acts by blocking the overstimulating effects of acetylcholine at the muscarinic... 

Cockcroft DW. Pharmacologic modulation of LPR muscarinic cholinergic antagonists. In Dorsch W, ed. Late Phase AUagic Reactions. Boca Raton, FL CRC Press,... 

Scopolamine A muscarinic cholinergic receptor antagonist that has amnesic side effects. 

Sanchez C, Arnt J, Didriksen M, Dragsted N, Lenz SM, Matz J (1998) In vivo muscarinic cholinergic mediated effects of Lu 25-109, a Ml agonist and M2/M3 antagonist in vitro. Psychopharmacology 137 233-240... 

Pharmacology Tolterodine is a competitive muscarinic receptor antagonist for overactive bladder. Urinary bladder contraction and salivation are mediated via cholinergic muscarinic receptors. 

Figure 5. Cartoon of a cholinergic synapse showing major steps in the synthesis of acetylcholine. The two major receptor types, the ionotropic nicotinic receptor and the metabotropic muscarinic receptor, are shown (see also Chapter 1). Presynaptic muscarinic (M2) and nicotinic receptors are also depicted. Drugs which have been widely used to manipulate the cholinergic systems, and which are mentioned in the text, include the muscarinic receptor antagonists scopolamine and atropine and the nicotinic receptor agonist nicotine. Anticholinesterases (discussed elsewhere in this volume) include drugs such as physostigmine, rivastigmine, donepezil, and galanthamine.

The TCA drugs have lost their place as first-line therapy for depression because of their bothersome side effects (Table 33.2) at therapeutic doses and lethal effects in toxic doses. In addition to their presynaptic effects on the neuronal uptake of norepinephrine and serotonin, they block several postsynaptic receptors. They are potent cholinergic muscarinic receptor antagonists, resulting in symptoms such as dry mouth, constipation, tachycardia, blurred vision and urinary retention. Blockade of histamine receptors (Hi) often results in sedation and weight gain. Antagonism of aj-adrenoceptors in the vasculature can cause orthostatic hypotension. 

Four different receptor types have been the main focus of interest. These are muscarinic cholinergic, histamine HI, dopamine D2 (different from the vascular dopamine receptor), and serotonin 5-HT3. In addition, neurokinin NKl-receptor antagonists are undergoing early clinical trials. 

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