title: A procedure for measuring alpha 2-adrenergic receptor-mediated inhibition of cyclic AMP accumulation in rat brain slices.
abstract: The alpha 2-adrenergic receptor regulation of cyclic adenosine monophosphate (cAMP) accumulation in rat brain slices was examined. using a prelabeling technique for measuring second messenger production. The mixed alpha-adrenergic agonist 6-fluoronorepinephrine, as well as the more selective alpha 2-agonists clonidine and UK-14,304, caused a concentration-dependent inhibition of forskolin-stimulated cAMP accumulation in cerebral cortical slices, whereas phenylephrine, a selective alpha 1-adrenergic agonist, had no inhibitory effect in this system. Moreover, alpha 2-adrenergic receptor antagonists were more potent than alpha 1-adrenergic antagonists in blocking the inhibitory response to UK-14,304. Neither alpha 1- nor alpha 2-adrenergic agonists displayed any inhibitory effect when cAMP accumulation was stimulated by isoproterenol, vasoactive intestinal peptide or 2-chloroadenosine. The results provide further evidence that some alpha 2-adrenergic receptors are negatively coupled to adenylate cyclase in brain, and yield a procedure for studying this phenomenon in intact central nervous system tissue.
mesh_terms: D015762:2-Chloroadenosine; D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D000068438:Brimonidine Tartrate; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008803:Mianserin / Q000494:pharmacology; D009638:Norepinephrine / Q000031:analogs & derivatives / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: D011810:Quinoxalines; D011942:Receptors, Adrenergic, alpha; D015762:2-Chloroadenosine; D005576:Colforsin; D008803:Mianserin; D014660:Vasoactive Intestinal Peptide; D000068438:Brimonidine Tartrate; C024884:6-fluoronorepinephrine; D000242:Cyclic AMP; D000241:Adenosine; D007545:Isoproterenol; D009638:Norepinephrine