SIGNAL INTEGRATION IN THE NERVOUS-SYSTEM - ADENYLATE CYCLASES AS MOLECULAR COINCIDENCE DETECTORS

Integrating multiple incoming messages simultaneously and discriminati ng 'meaningful' signals from spontaneous neural activity represent cen tral problems to the nervous system. One mechanism by which signal int egration and signal-to-noise resolution are achieved is the formation of temporal coincidence circuits by interacting transduction pathways. Signal integration via temporal coincidence detection is exemplified most readily by the way in which neural adenylate cyclases are regulat ed. This review will discuss the role of adenylate cyclases as coincid ence detectors in the nervous system with special focus on adenylate c yclase type III, an isoenzyme that is found in large quantities in olf actory receptor neurons. The notion that olfactory transduction might also utilize an adenylate-cyclase-mediated temporal coincidence circui t strengthens the idea that signal integration via temporal-coincidenc e pathways is a universal feature of all neural adenylate cyclases.