The possibility that clathrin plays a role in the agonist-mediated sequestration of muscarinic cholinergic receptors in human SH-SY5Y neuroblastoma cells has been investigated by the application of experimental paradigms previously established to perturb clathrin distribution and receptor cycling events. Preincubation of SH-SY5Y cells under hypertonic conditions resulted in a pronounced inhibit...

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...

Although the heart is considered a relatively pure source of m2 muscarinic receptors, the possible expression of other muscarinic receptor genes at discrete sites within the myocardium or by intrinsic cardiac ganglia had not been evaluated. Accordingly, the present study used in situ hybridization histochemistry with "S-labeled oligonucleotide probes to address this issue. Initial experiments d...

The first step in the transmembrane signal mediated by G protein-coupled receptors is binding of agonist to receptors at the cell surface. The mechanism of the resulting receptor activation is not clear, but models based on the ternary complex model are capable of explaining most of the observations that have been reported in G protein-coupled receptors. This model suggests that a single agonis...

Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cholinergic receptor protein affinity labeled with the muscarinic antagonist [3H]propylbenzilylcholine mustard revealed a major polypeptide with molecular weight of 80,000-83,000 in both acinar carcinoma and normal acinar cells of rat pancreas. Muscarinic receptor protein is therefore conserved in pancreatic acinar carcino...

The study was carried out to desensitize spontaneously active isolated chick rectum with salbutamol in log doses starting from 100 nanogram and resensitize with various drugs as a result to revive the desensitized tissue and respond to Salbutamol. The tissue response after desensitization to alpha, beta adrenergic and muscarinic acetylcholine receptor antagonists was isotonically recorded for 1...

Neurotransmitter receptor functional regulation plays an important role in controlling the excitability and responsiveness of hippocampal neurons. Deregulation of its function is associated with seizure generation, motor deficits, and memory impairment. In the present study we investigated the changes in hippocampal cholinergic and GABA receptor binding and gene expression in insulin-induced hy...

There are still many question open to completely understand the structure-activity relationships of G-protein coupled receptors. Issues like the actual mapping of the binding site of different subtypes, as well as the mechanism of activation are poorly understood [1]. Accordingly, further studies on the structure-activity relationships are necessary. In this regard, only a few 3D structures are...

The naked mole-rat (Heterocephalus glaber) is a promising animal model for the study of pain mechanisms, therefore a thorough characterization of this species is essential. The aim of the present study was to establish the naked mole-rat as a model for studying the cholinergic receptor system in antinociception by investigating the involvement of muscarinic, nicotinic and opioid receptors in no...