Sustained stimulation of the b -adrenoceptor leads to a desensitization of the receptor-mediated adenylyl cyclase stimulation. While 2 desensitization promoted by nanomolar concentrations of isoproterenol involves the phosphorylation of the b -adrenoceptor by protein 2 kinase A alone, both protein kinase Aand b-adrenoceptor kinase-mediated phosphorylation leading to the binding of b-arrestin co...

The homologous and heterologous desensitization of rat Leydig-tumour-cell adenylate cyclase induced by lutropin (LH) was characterized with the aid of forskolin and cholera toxin. Forskolin stimulated cyclic AMP production in a dose-dependent manner, with linear kinetics up to 2 h. Forskolin also potentiated the action ofLH on cyclicAMP production, but was only additive with cholera toxin. Prei...

Yan, Weihong, Chinnaswamy Tiruppathi, Hazel Lum, Renli Qiao, and Asrar B. Malik. Protein kinase Cb regulates heterologous desensitization of thrombin receptor (PAR-1) in endothelial cells. Am. J. Physiol. 274 (Cell Physiol. 43): C387–C395, 1998.—We studied the effects of protein kinase C (PKC) activation on endothelial cell surface expression and function of the proteolytically activated thromb...

Background:Aspirin exacerbated respiratory disease (AERD) affects up to 5% to 15% of asthmatics. While aspirin desensitization is a safe treatment option and allows for aspirin to be used to control AERD symptoms, not all patients diagnosed with AERD are able to complete the standard desensitization protocol. Objective: For patients who cannot complete the standard desensitization protocol, we ...

When dopamine D1 and D2 receptors were coactivated in D1-D2 receptor hetero-oligomeric complexes, a novel phospholipase C-mediated calcium signal was generated. In this report, desensitization of this Gq/11-mediated calcium signal was demonstrated by pretreatment with dopamine or with the D1-selective agonist (+/-)-6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide...

Long-term infusion of prostacyclin, or its analogs, is an effective treatment for severe pulmonary arterial hypertension. However, dose escalation is often required to maintain efficacy. The aim of this study was to investigate the mechanisms of prostacyclin receptor desensitization using the prostacyclin analog cicaprost in rat pulmonary artery smooth muscle cells (PASMCs). Desensitization of ...

Acute desensitization of contraction and its relative mechanisms have been studied in smooth muscle cells isolated from guinea pig stomach. Desensitization was induced by pre-exposure of the cells to one of the excitatory neuropeptides linked to the phospholipase C intracellular cascade, i.e., cholecystokinin (CCK), gastrin-releasing peptide, and Substance P. Desensitization was homologous afte...

cytotoxic effects of obturation materials were tested in presence and absence of endotoxin on human monocytes in vitro.human monocytes from thp-1 cell line were cultured. three millimeters from the tip of each resilon and gutta percha points were cut and directly placed at the bottom of the culture wells. cultured cells were exposed to gutta percha (groups g1 and g2) and resilon (r1 and r2). te...