Catecholamine binding to CNS adrenergic receptors

Publisher Website
Google Scholar
Abstract
The properties of 3H‐catecholamine binding to α‐ and β‐adrenergic receptors in CNS are reviewed. 3H‐epinephrine and 3H‐norepinephrine label one class of α‐receptors throughout the brain, with high affinities for agonists and some antagonists. Agonist affinities at this site are increased in low temperature conditions but are reduced by guanine nucleotides and monovalent cations. Divalent cations reverse both effects. This α‐receptor may be coupled to adenylate cyclase by GTP and/or sodium, and uncoupled by divalent cations. 3H‐epinephrine labels β2, but not β1, receptors in CNS, especially in bovine cerebellum. The same β‐receptor does not show agonist‐specific GTP‐sensitivity, but does exhibit Na+‐sensitivity. This receptor appears to be linked to adenylate cyclase, and sodium rather than GTP may be the coupling agent.