PURPOSE Muscarinic receptors are known to regulate several important physiologic processes in the eye. Antagonists to these receptors such as atropine and pirenzepine are effective at stopping the excessive ocular growth that results in myopia. However, their site of action is unknown. This study details ocular muscarinic subtype expression within a well documented model of eye growth and inves...

The selectivity profiles of the muscarinic receptor antagonists dicyclomine and trihexyphenidyl have been examined in binding and functional studies and compared with those of pirenzepine and atropine. Dicyclomine, trihexyphenidyl and pirenzepine demonstrated the highest affinity for the M1 muscarinic receptor subtype as revealed in competition experiments against [3H]-pirenzepine labelling of ...

Acetylcholine may play a role in cell activation and airway inflammation. We evaluated the levels of both mRNA and protein of muscarinic M(1), M(2), M(3) receptors in human bronchial epithelial cell line (16HBE). 16HBE cells were also stimulated with acetylcholine and extracellular signal-regulated kinase1/2 (ERK1/2) and NFkB pathway activation as well as the IL-8 release was assessed in the pr...

Overactive bladder (OAB) is a common, costly, and treatable condition in older persons. There is a wide array of available antimuscarinics for the treatment of these conditions; however, their side effect profile and the limited number of studies that evaluate their effect in the elderly curb their use. This review article focuses on OAB and its treatment, with special attention to the use of a...

Previous experiments have demonstrated that the rat dorsomedial striatum is one brain area that plays a crucial role in learning when conditions require a shift in strategies. Further evidence indicates that muscarinic cholinergic receptors in this brain area support adaptations in behavioral responses. Unknown is whether specific muscarinic receptor subtypes in the dorsomedial striatum contrib...

Recent pharmacological studies exploring the functional roles of muscarinic cholinergic receptor (mAChR) subtypes in prefrontal cortex of C57BL/6J (B6) mouse have provided evidence for a presynaptic M2 autoreceptor. The B6 mouse was chosen for these studies because it is a genetically well-characterized model that also provides the genomic background for many genetically modified mice. In addit...

Based on the existence of choline acetyltransferase and acetylcholine in human placenta, we have investigated the presence of muscarinic acetylcholine receptors in brush-border and basal plasma membranes from human term placenta. Radioligand binding assay, using [3H]N-methyl-scopolamine as tracer, showed the existence of acetylcholine muscarinic receptors in brush-border (Kd 0.28 +/- 0.04 nM; B...

The high-affinity muscarinic antagonist L-[3H]quinuclidinyl benzi-late (L-[3H]QNB) was used to label muscarinic acetylcholine receptors in the astrocyte-enriched fraction isolated from rat hippocampus. Analysis of the saturation and drug inhibition data showed that [3H]QNB binding in the astroglia fraction was saturable, of high affinity (Kd = 0.026 nM) and competitively inhibited by muscarinic...

A patient with widespread smooth-muscle disease presented with chronic intestinal pseudo-obstruction but had in addition defects of the bladder, pupils, sweating, and cardiovascular function. There was no evidence of a primary neural lesion, and minor changes in the muscle did not resemble those of a myopathy. In each organ affected muscarinic cholinergic function was at fault, but instead of s...

The chronotropic response of embryonic chick hearts to cholinergic agents is first clearly detectable on day 5 in ouo and full responsiveness develops by day 7. Muscarinic acetylcholine receptors in fully responsive 9day-old hearts specifically bind the muscarinic antagonist quinuclidinyl benzilate. Binding is blocked effectively by muscarinic agonists and antagonists but is poorly inhibited by...