Figure 7. Atracurium inhibits intracellularly recorded GABA^AIPSPs. (A) Blockade by atracurium of the GABA^A-mediated IPSP evoked by orthodromic stimulation of Schaffer collaterals. The cell input resistance was assessed by measuring the voltage deflection elicited by a short pulse of hyperpolarizing current (0.2 nA). The graph shows the amplitude of the IPSP measured at the peak of the hyperpolarization before, during, and after atracurium application (black bar). Values from eight consecutive measurements were averaged and expressed as percent of baseline pre-drug values. Top traces are representative potentials (average of six) recorded before (a) and during (b) atracurium application. (B and C) Bar graphs showing respectively, the changes in size of the intracellular IPSP and in input resistance observed in a group of six similar experiments (ctrl = control).