NOcGMPSignalweg

The NOcGMP signaling pathway, also known as the nitric oxide-cyclic guanosine monophosphate (cGMP) pathway, is a crucial cellular signaling cascade involved in various physiological processes. This pathway is initiated by nitric oxide (NO), a free radical gas produced by nitric oxide synthases (NOS) from the amino acid L-arginine. NO can diffuse across cell membranes and act as a paracrine or autocrine messenger.

Upon entering a target cell, NO activates an enzyme called soluble guanylate cyclase (sGC). This activation leads to an increase in intracellular levels of cGMP, which acts as a second messenger. cGMP then mediates a range of cellular responses, depending on the specific cell type. Key downstream targets of cGMP include protein kinase G (PKG), cyclic nucleotide-gated ion channels (CNGs), and phosphodiesterases (PDEs).

The NO-cGMP pathway plays significant roles in vascular smooth muscle relaxation, thereby regulating blood pressure and blood flow. It is also involved in neurotransmission, immune responses, and platelet aggregation. Dysregulation of this pathway has been implicated in various diseases, including cardiovascular disorders, erectile dysfunction, and neurological conditions. The breakdown of cGMP is primarily regulated by phosphodiesterases, which hydrolyze cGMP back to its inactive form, GMP, thus terminating the signal.