Specific [3H]UK 14,304 binding in human cortex occurs at multiple high affinity states with alpha 2-adrenergic selectivity and differing affinities for GTP.
[3H]UK 14,034 is a full agonist at alpha 2-adrenergic receptors. Although the characteristics of the binding of the partial alpha 2-adrenergic agonists in postmortem human brain were known, the binding of [3H]UK 14,304 had not been studied in this tissue. Multi-site binding of this radiolabel had been reported in other tissues and guanosine triphosphate (GTP) had been shown to reduce [3H]UK 14,304 binding. We now report that [3H]UK 14,304 labels at least 2 specific binding sites in human brain that both have the characteristics of an alpha 2-adrenergic binding site. GTP decreases agonist binding at both of these sites, but with different potencies at each site.
Andorn
A C
AC
Department of Psychiatry, Case Western Reserve University School of Medicine, Cleveland, Ohio.
Carlson
M A
MA
Gilkeson
R C
RC
D000316:Adrenergic alpha-Agonists / Q000378:metabolism; D000068438:Brimonidine Tartrate; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D011810:Quinoxalines / Q000378:metabolism*; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*
D000316:Adrenergic alpha-Agonists; D011810:Quinoxalines; D011942:Receptors, Adrenergic, alpha; D000068438:Brimonidine Tartrate; D006160:Guanosine Triphosphate