SINGLE GLUTAMATE CHANNELS IN CA1 PYRAMIDAL NEURONS AFTER TRANSIENT ISCHEMIA

PATCH clamp recordings were made from CA1 pyramidal neurones to study changes in the glutamate receptor subtypes in the gerbil hippocampus a fter transient ischaemia. In whole-cell recordings, the maximum chord conductances of AMPA currents in ischaemic neurones were increased ove r those of control neurones but NMDA-induced currents in the ischaemic neurones were smaller than the control. In AMPA-activated single chan nel currents, an open time histogram of the control neurones was well fitted by a single exponential function whereas in the ischaemic patch es it was fitted by a double exponential function, indicating that cur rents consisted of at least two kinetically different types. These fun ctional changes of the glutamate receptor channels may contribute to t he abnormalities of the excitatory synaptic currents recorded in post- ischaemic CA1 neurones.