Adrenoceptors and signal transduction in neurons.
The adrenergic system is an essential regulator of neuronal, endocrine, cardiovascular, vegetative, and metabolic functions. The endogenous catecholamines epinephrine and norepinephrine activate G-protein-coupled receptors to transmit their signal across the plasma membrane. These adrenoceptors can be divided into three different groups: the alpha(1)-receptors (alpha(1A), alpha(1B), alpha(1D)), alpha(2)-receptors (alpha(2A), alpha(2B), alpha(2C)), and beta-receptors (beta(1), beta(2), beta(3)). This review summarizes recent findings in the field of adrenoceptor signaling in neurons and includes a discussion of receptor-associated proteins, receptor dimerization, subcellular trafficking, and fluorescence optical methods for studying the kinetics of adrenergic signaling. Spatio-temporal imaging may become an important future tool for identifying the physiological significance of these complex signaling mechanisms in vivo. Gene-targeted mouse models carrying deletions in alpha(2)-adrenoceptor have provided detailed insights into specific neuronal functions of the three alpha(2)-receptor subtypes.
Hein
Lutz
L
Institut für Exp. und Klin. Pharmakologie und Toxikologie, Universität Freiburg, Albertstrasse 25, 79104 Freiburg im Breisgau, Germany. lutz.hein@pharmakol.uni-freiburg.de
D000818:Animals; D004837:Epinephrine / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D021962:Membrane Microdomains / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D011941:Receptors, Adrenergic / Q000172:deficiency / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D011941:Receptors, Adrenergic; D004837:Epinephrine