Fig. 7
Effect of histamine on cAMP generation in transfected L cells
Histamine had no effect on nontransfected L cells, but stimulated cAMP formation in L cells transfected with the wild-type H2 receptor in a fashion that could be inhibited by cimetidine (data not shown). Histamine also stimulated cAMP formation in L cells transfected with the Ala186-Ser187 mutant H2 receptor in a dose-dependent fashion (ED50 = 5 × 10−8 M). The response to histamine was inhibited by both propranolol and cimetidine. Data are represented as means ± SEM, n = 4.