Guanosine 3',5'-cyclic monophosphate sodium salt is widely used in biochemical research as a second messenger to study intracellular signaling pathways, particularly those involving cyclic GMP (cGMP). It plays a critical role in investigating processes like vasodilation, neurotransmission, and cellular regulation. In pharmacological studies, it is employed to explore the effects of cGMP-dependent protein kinases and phosphodiesterases, aiding in the development of drugs targeting cardiovascular diseases, erectile dysfunction, and pulmonary hypertension. Additionally, it is utilized in cell culture experiments to understand its role in modulating smooth muscle relaxation and platelet aggregation. Its application extends to neuroscience, where it helps elucidate mechanisms of neuronal communication and synaptic plasticity.