Adrenergic agonists induce heterologous sensitization of adenylate cyclasein NS20Y-D-2L cells

Adenylate cyclase activity in NS20Y cells expressing D-2L dopamine receptor s was examined following chronic treatment with norepinephrine and epinephr ine. Initial acute experiments revealed that both norepinephrine and epinep hrine inhibited forskolin-stimulated cyclic AMP accumulation via D-2 recept ors, Furthermore, chronic(18 h) activation of D-2 dopamine receptors by nor epinephrine or epinephrine induced a marked increase (> 10-fold) in subsequ ent forskolin-stimulated cyclic AMP accumulation. Tills heterologous sensit ization of adenylate cyclase activity was blocked by D-2 dopamine receptor antagonists and by by pertussis toxin pretreatment, In contrast, concurrent activation of G alpha (s) or adenylate cyclase did not appear to alter nor adrenergic agonist-induced sensitization. (C) 2001 Published by Elsevier Sc ience B.V. on behalf of the Federation of European Biochemical Societies.