Fig. 2.

Reversal potential of GABAergic currents in NM neurons is more positive than that found in other neurons. A, Gramicidin–perforated-patch voltage-clamp recordings of GABAergic currents evoked by synaptic stimulation. Membrane potential was held at different voltages, and average current amplitude (10 trials) was measured 5 msec after the last stimulus (outlined by vertical bar).B, Gramicidin–perforated-patch recordings from a reticular formation neuron in a slice from the same animal show that GABAergic currents reverse at a more hyperpolarized membrane potential.Traces shown are recorded at holding potentials of −91, −76, −68, −59, and −49 mV. Inset shows that the reversal potential changes to more a positive value after patch rupture ([Cl⁻] pipette of 37 mm).C, NM data (diamonds) fit with a linear regression gives a V_rev of −37 mV, whereas GABAergic currents in a brainstem neuron (circles) show a more hyperpolarizedV_rev of approximately −65 mV.D, Mean ± SEM V_rev for GABAergic currents in NM neurons was −36 ± 2.1 mV. Auditory neurons in the SON and other brainstem neurons had more hyperpolarized V_rev averages of −61 ± 4.3 and −72 ± 4.7, respectively (note that currents recorded in the presence of DNQX and APV).