Fig. 4.

Conductance oscillations are abolished in recordings using glyburide-filled electrodes. A and B: membrane potential and slope conductance oscillations recorded using the holding potential ramp (HPR) protocol in 11.1 mM glucose with a standard electrode. C and D: membrane potential and slope conductance recorded in the same islet and glucose concentration as shown in A but using a glyburide-filled electrode (200 μM); electrical oscillations were preserved, but conductance oscillations were abolished in 5 of 6 islets tested. Membrane potential oscillations that occur in neighboring cells are presumed to be transmitted to the voltage-clamped cell through gap junctional coupling. The hypothesis that conductance oscillation amplitude was lower in glyburide than in control was significant by unpaired t-test with P = 0.03 (0.118 ± 0.04 vs. 0.051 ± 0.06 nS).