Fig. 3. Modulation of cyclic-nucleotide-gated (CNG) channels by tyrosine phosphorylation. (A) Changes in amplitude of cGMP-activated current through CNG channels in an excised membrane patch. Currents were elicited by application of cGMP at concentrations of 50, 100, 250 and 2000µmoll^-1 and recorded 1 and 10min after patch excision and after a 3min application of 200µmoll^-1 ATP. (B) Changes in cGMP-sensitivity of CNG channels after patch excision and subsequent transient application of ATP. (C) Changes in the cyclic-nucleotide-sensitivity (K_1/2) exhibited during the first 10min after excision in the presence of serine/threonine and tyrosine protein kinases and phosphatases inhibitors. Values are means + S.E.M. (N=6–16 for different inhibitors).