Second messenger-mediated actions of norepinephrine on target neurons in central circuits: a new perspective on intracellular mechanisms and functional consequences.

摘要: Ever since the initial demonstration of a widespread distribution noradrenergic fibers to functionally diverse regions mammalian forebrain, there has been considerable interest in determining electrophysiological effects norepinephrine (NE) on individual neurons within these target areas. While early studies showed that NE could directly inhibit cell firing via increased intracellular levels cyclic AMP, more recent work revealed spectrum actions, which are accurately characterized as neuromodulatory. More specifically, numerous experimental conditions have described where at subthreshold for producing direct depressant spontaneous can facilitate neuronal responses both excitatory and inhibitory synaptic stimuli. The goal this report is review evidence suggests various modulatory actions central result from activation different adrenoceptor-linked second messenger systems. In particular, we focused candidate signal transduction mechanisms may underlie NE's ability augment cerebellar cortical responsiveness GABAergic inputs. consequences such NE-induced changes efficacy considered not only with respect their influences feature extraction properties sensory but also regard potential impact would processing capabilities network noradrenergically innervated cells.