Welcome all to IS PHARMACOLOGY DIFFICULT Podcast! I am Dr Radhika Vijay, in today's episode, I will limit my talks in a short crispy description about cGMP(cyclic GMP) as a second messenger. cGMP is an intracellular second messenger in a limited number of tissues, like vascular smooth muscle, intestinal mucosal cell and kidney, where it respectively serves to perform actions like smooth muscle relaxation, inhibition of salt and water absorption in mucosal cell, in kidney it mediates natriuresis in kidney. Two principal forms of guanylyl cyclases(GC). In turn cGMP is generated. cGMP has two isoforms , one being bound to cell membrane and the other as cytosolic form, none is regulated by GPCR. Cell membrane bound guanylyl cyclase is regulated by transmembrane enzyme linked receptor for ANP. Cytosolic one is activated by NO. After generation by endothelial cells, NO diffuses in adjacent smooth muscles cells, stimulates guanylyl cyclase. increased cGMP, dephosphorylates MLCK, induces relaxation. This pathway is utilised by drug like sodium nitroprusside. Well that was all dear listeners, hope I am able to feed your ears with the right flow of knowledge waves, information and facts, hope you all like this session, short, but important, till next episode, do follow me here, stay tuned, do rate and review on Ituned, Apple podcast, thank you!!