Figure 6.

Apparent activation of IP₃ production (A) and intracellular Ca²⁺ recruitment by KMD-3213 in prazosin-pretreated CHO cells expressing the mutant alpha-1a AR. CHO cells expressing the mutant alpha-1a AR were preincubated for 48 h with 10 nM prazosin and then 100 nM KMD-3213 was added under the continued presence of prazosin. Level of IP₃ and intracellular [Ca²⁺] were estimated as described under Methods. In (A) data represent the mean±s.e.mean from three experiments. The asterisk indicates a significant (P<0.05) increase of IP₃ from the value at 0 time. In (B) a representative result of three experiments was shown. The response of the mutant clone without the prazosin pretreatment and in the absence of prazosin was depicted with dotted line. At the end of experiments, 10 μM UTP was administered to confirm the ability of the cells to increase intracellular [Ca²⁺].