Fig. 2. -Adrenergic stimulation but not ß-adrenergic stimulation induces the hsp70 gene promoter in oyster immune cells. Luciferase activity increased in transfected cells exposed to the -adrenoceptor agonist PE (A), but not in cells exposed to the ß-adrenoceptor agonist isoproterenol (B). Pretreatment with the -adrenoceptor antagonist prazosin blocked the NA-induced increase in luciferase activity (C), whereas pretreatment with the ß-adrenoceptor antagonist propanolol had no significant effect (D). Data are means and standard errors of three replicate experiments. Asterisks denote significant (P<0.01) differences from samples incubated in the absence of agonist (A,B) or in the presence of 1 µM NA alone (C,D). Bas indicates luciferase activity in samples incubated in the absence of drugs.