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Recent studies have demonstrated that many electrophysiological characteristics of phramidal neurons in hippocanmpalCAl region are changed after transient forebrain ischemia.Large conductance calcium-adtivated potassium(BK_(Ca))channel plays critical roles insetting neuronal electrophysiological properties.Here we examined whether activity of BK_(Ca) channel in CA1 pyramidal neurons of adult rat hip-pocampus changed after transient forebrain ischemia using inside-out configuration of patch clamp techocniques.The results were as follows:(a)Alternation in sensitvity to [Ca~(2+)],was found when the [Ca~(2+)]_i.required to half activate(P_0=0.5)BK_(Ca) channel increased from 2×10~(-6)M to1×10~(-6)M and voltage dependence of BK_(Ca)channel showed no obvious change after ischewia;(b)The unitary conductance of BK_(Ca) channel in-creased by about 20% (from 245 pS to 295 pS in symmetrical 14O/140mM K~+ in inside-out patch)after ischemia;(c)Mean open time of BK_(Ca)channel increased from 12.20 ms to 17.32ms,and
Recent studies have demonstrated that many electrophysiological characteristics of phramidal neurons in hippocanal CA1 region were changed after transient forebrain ischemia. Larger conductance calcium-adtivated potassium (BK_ (Ca)) channel plays a critical role in setting out neuronal electrophysiological properties. Here we examined whether activity of BK_ ( Ca) channel in CA1 pyramidal neurons of adult rat hip-pocampus changed after transient forebrain ischemia using inside-out configuration of patch clamp techiques. These results were as follows: (a) Alternation in sensitvity to [Ca ~ (2+)], was found when the [Ca ~ (2 +)] _ i.required to half activate (P_0 = 0.5) BK_ (Ca) channel increased from 2 × 10 -6 M to 1 × 10 -6 M and voltage dependence of BK_ (Ca) channel showed no obvious change after ischemic; (b) The unitary conductance of BK_ (Ca) channel in-creased by about 20% (from 245 pS to 295 pS in symmetrical 14O / 140 mM K ~ + in inside -out patch) after ischemia; (c) Mean open time of BK_ (Ca) channel increased from 12.20 ms to 17.32ms, and