[Effects of 17 beta-estradiol on delayed rectifier potassium channels in hippocampal pyramidal neurons of the rat].

In the present study, both cell-attached and inside-out patch-clamp techniques wereused to detect the effects of 17β-estradiol (E2) on 42 pS delayed rectifier potassiumchannels in acutely dissociated hippocampal neurons of new-born SD rats. The resultsindicated that after application of 1 .0 and 10.0 nmol/L E2, the open probabilities of K+channels were decreased from (67.4 ± 18.2) % to (41 .2 ± 12.5) % and from (56.3 ±15.8) % to (13.2 ± 12.6) % respectively, the open frequencies were reduced from(43.40 ± 6.7) Hz to (27.68 ± 9. 1) Hz and from (38. 19 ± 10. 1) Hz to (15.79 ± 3.5)Hi respectively. Meanwhile, there was a shortening of the mean open time and alenghtening of the mean close time of the channels. The above results suggest that E2 hassuppressive effects on the activities of the channels, which might be exerted through adirect action on the cellular membrane.