The effect of E2 is estrogen receptor specific and dependent on protein tyrosine phosphorylation. Prior addition of 1μM ICI 182,780 (ICI), a highly specific estrogen receptor antagonist, prevented the effect of E2. Prior treatment with 1μM lavendustin (LAV), a general tyrosine kinase inhibitor, markedly attenuated the response. Right panel shows the time course. Left panel shows the effect at 30 min post E2 addition. Mean currents at t=0 were -452 ± 141 (n=5) and -405 ± 110 (n=5) for the neurons treated ICI 182,780 and lavendustin, respectively. Significantly different from E2-treated neurons: *, P<0.05; **, P<0.01.