Cyclic nucleotides are small, intracellular signaling molecules that play a crucial role in a variety of physiological processes. They are formed from adenine or guanine nucleotides and contain a cyclic phosphate moiety. The two most common cyclic nucleotides are cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). They act as second messengers in cell signaling pathways, which regulate a range of cellular processes such as metabolism, gene expression, ion channel function, and regulation of protein kinases. Cyclic nucleotides can also be targeted therapeutically to treat a variety of disorders, including heart disease, asthma, and erectile dysfunction.
