Alpha 2-adrenoceptors in human forebrain: autoradiographic visualization and biochemical parameters using the agonist [3H]UK-14304.

The regional distribution and biochemical parameters of alpha 2-adrenoceptors in post-mortem human brain tissue were analyzed in autoradiographic and membrane binding studies, using the full agonist, [3H]UK-14304. Autoradiographic visualization of these receptors in the forebrain revealed a heterogeneous anatomical distribution with high levels in the neocortex, ventral hypothalamus, hippocampus and some thalamic nuclei, among others. In membrane binding studies, analyses of saturation curves indicated the presence of a single population of sites for [3H]UK-14304 both in the human and rat brain. There was a good correlation between the density of alpha 2-adrenoceptors obtained by both procedures. [3H]UK-14304 is a feasible ligand to localise and quantify alpha 2-adrenoceptors in human post-mortem material by autoradiographic and membrane binding techniques.