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 ...

Muscarinic cholinergic receptors modulate dopaminergic function in brain pathways thought to mediate cocaine’s abuse-related effects. Here we sought to confirm and extend in the mouse species findings that nonselective muscarinic receptor antagonists can enhance cocaine’s discriminative stimulus. More importantly, we tested the hypothesis that muscarinic receptor agonists with varied receptor s...

Muscarinic cholinergic receptors modulate dopaminergic function in brain pathways thought to mediate cocaine’s abuse-related effects. Here we sought to confirm and extend in the mouse species findings that nonselective muscarinic receptor antagonists can enhance cocaine’s discriminative stimulus. More importantly, we tested the hypothesis that muscarinic receptor agonists with varied receptor s...

Some studies have shown that acetylcholine muscarinic receptors involved in the opiate reward. In the present study, the effect of intra-basolateral amygdale (BLA) acetylcholine muscarinic like receptor agonist (physostigmine) and antagonist (atropine) on the acquisition of morphine-induced place preference has been investigated in male Wistar rats. For this purpose, two 22 gauges guide cannula...

BACKGROUND Alterations in muscarinic receptor expression and acetylcholinesterase (AchE) activity have been observed in tissues from Sudden Infant Death Syndrome (SIDS). Vagal overactivity has been proposed as a possible cause of SIDS as well as of vasovagal syncopes. The aim of the present study was to seek whether muscarinic receptor overexpression may be the underlying mechanism of vagal hyp...

Pertussis toxin was used to examine the role of the inhibitory guanine nucleotide regulatory protein, Ni, in muscarinic-receptor-mediated stimulation of phosphoinositide turnover and calcium mobilization. In cultured chick heart cells, pertussis-toxin treatment inhibited muscarinic-receptor-mediated attenuation of isoprenaline-stimulated cyclic AMP accumulation. This finding is consistent with ...

Acetylcholine is the primary parasympathetic neurotransmitter in the airways and is known to cause bronchoconstriction and mucus secretion. Recent findings suggest that acetylcholine also regulates aspects of remodelling and inflammation through its action on muscarinic receptors. In the present study, we aimed to determine the effects of muscarinic receptor stimulation on cytokine production b...

Characteristics of muscarinic acetylcholine (ACh) receptors were studied in the rat central nervous system (CNS) using 3H-quinuclidinyl benzilate (QNB), an antagonist of muscarinic ACh receptors. Scatchard analysis indicated that the rat CNS had a single 3H-QNB binding site with an apparent dissociation constant (Kd) of 5.0 X 10(-10) M. Li+, Zn++ and Cu++ had strong effects on 3H-QNB binding wh...

Receptor-mediated changes in cytoplasmic calcium concentrations occur either through release from intracellular calcium stores or by the opening of channels in the plasma membrane, allowing influx of calcium from the extracellular fluid. Carbachol, a muscarinic receptor agonist, stimulated both calcium influx and inositol 1,4,5-trisphosphate (InsP3)-mediated intracellular calcium release in A9 ...

BACKGROUND A safe and effective ultra-short-acting nondepolarizing neuromuscular blocking agent is required to block nicotinic receptors to facilitate intubation. Rapacuronium, which sought to fulfill these criteria, was withdrawn from clinical use due to a high incidence of bronchospasm resulting in death. Understanding the mechanism by which rapacuronium induces fatal bronchospasm is imperati...