Welcome all to IS PHARMACOLOGY DIFFICULT Podcast! I am Dr Radhika Vijay, in today's episode, I will be starting with a sort of revision of GPCR, well, truly speaking, there is also added information to the topic, hence revision with addition is the motto, In the starting of episode, I will be introducing a new name for these receptors namely Metabotropic receptors. Then starting with the diagrammatic depiction and sound basis of the mechanism, I will be telling you all that G proteins are coupled with effectors like enzymes etc. GPCRs are composed of 7 transmembrane helices with an extracellular domain as drug binding site and an intracellular domain coupled to G protein, which are heterotrimeric in nature, written as alpha-beta-gamma subunit. Further alpha subunit varieties make these distinct, Gs, Gi, Gq. They have their distinct activities. When GPCR is in resting state, GDP is bound to alpha subunit. When an agonist binds, exchange of GTP for GDP occurs, then beta-gamma subunit dissociates from this, alpha GTP complex finally interacts with the target protein and activates it. That was all a quick revision of diagram and starting mechanism of GPCR, hope it helped you all with all added information, till next episode, do follow me here, stay tuned, do rate and review on ITunes, Apple podcasts, thank you!!