Fig. 2. Dose–response curves to phenylephrine in secretory cells in different stages of the venom production cycle: quiescent cells (filled squares, N=11), cells collected just after venom extraction (open triangles, N=6), cells collected 4 days (open circles, N=6), 7 days (open diamonds, N=5), 15 days (asterisks, N=6) and 30 days after venom extraction (filled circles, N=6). Note that venom extraction induced receptor downregulation that lasted for at least 15 days. Values are means ± S.E.M.