GPCRs in rat primary skeletal muscle cells

GPCRs are the largest family of proteins in the human genome and a target for huge numbers of therapeutic drugs. However, the role of skeletal muscle in the action of these drugs is unclear. Given the unique importance of GPCR signalling in terms of glucose and fatty acid turnover in other tissues, it would be anticipated that GPCR identified to influence metabolism in these tissues might well be expressed in skeletal muscle. This study investigated the expression of genes encoding GPCRs in skeletal muscle and in cultured preparations thereof. In particular, this study focussed on the expression and signalling of adenosine receptors, a2-adrenoceptor, P2Y receptors and CBI cannabinoid receptors and the impact of CBI receptor modulation upon insulin signalling in rat primary skeletal muscle cells. All experiments in this work looked at GPCR expression and their signalling; with either tissues or cultured cells from rats. These experiments included: 1. Transcriptional profiling of skeletal muscle tissue in Wistar rats for GPCRs and proteins in associated signalling pathways. 2. Signalling of GPCRs (adenosine, a2A-adrenoceptor, P2y) in rat primary skeletal muscle cells. 3. Cannabinoid signalling pathways and cross-talk with insulin signalling. 4. CBI cannabinoid receptor antagonist/inverse agonist/agonist treatment of rat primary skeletal muscle cells. Expression of example members of the three major G protein coupling GPCR families was observed in rat skeletal muscle tissue. mRNA encoding Gs- (A2Aadenosine receptor, P2-adrenoceptor), Gi- (AI adenosine receptor, (l2A-adrenoceptor), and Gq-coupled (P2Y 1. P2Y2 and P2Y6 receptors) receptors were detected using gene microarray (Agilent, all ranked