Interrelationships of Cyclic GMP, Inositol Phosphates, and Calcium

This chapter discusses the cyclic GMP effects on the Ca²⁺ or inositol phosphate pathways. Cellular functions are regulated by neurotransmitters, hormones, and a wide variety of regulatory and growth-promoting factors. The agonists produce a host of physiological responses in their target tissues because of their interactions with specific cell-surface receptors. Despite the numerous agonists and their specific receptors, the transmembrane signaling mechanisms can be categorized into relatively few pathways. Thus, interactions among these signaling pathways must occur to explain a remarkable diversity of cellular responses that are evoked by a variety of agonists through a simple signaling pathway. These interactions among transmembrane signaling pathways are called “cross-talk,” and a large body of evidence for various types of cross-talk has been accumulating. The cyclic GMP signal transduction system also regulates the Ca²⁺ or inositol phosphates pathways.