Fig. 6. Gap junctions provide follicle-enclosed oocytes with access to mechanisms that correct acidosis. SNARF-dextran was microinjected into denuded and follicle-enclosed oocytes from day-10 mice. (A) Recovery from acidosis was examined simultaneously in denuded and follicle-enclosed oocytes from day-10 mice using SNARF-dextran in bicarbonate-free medium. The graph shows a representative replicate of this experiment, in which six follicle-enclosed (black traces) and five denuded oocytes were examined. The follicle-enclosed oocytes recover from acidosis when Na⁺ is replaced. The average rate of recovery following Na⁺-replacement is significantly greater in the follicle-enclosed oocytes over the course of three replicates (P<0.05). Note that the SNARF-dextran remains restricted to the oocyte within the follicle (inset). (B) Recovery from acidosis was examined in follicle-enclosed oocytes in the presence of DMSO (left panel) or 150 µM AGA (centre), which were added during the experiment at t=20 minutes. A representative replicate of each treatment group is shown. (C) Analyses of the rate of pH recovery during the Na⁺-free period and following Na⁺ replacement are shown. Each bar represents the mean of three separate replicates, a total of 19-29 follicle-enclosed oocytes. Different letters above bars indicate significant differences (ANOVA, P<0.01). Note that gap-junction inhibition abrogates both Na⁺-dependent and Na⁺-independent phases of acidosis recovery in follicle-enclosed oocytes. Note also that AGA does not inhibit acidosis recovery in fully grown oocytes, or shells of granulosa cells (B, right, one of two similar experiments is shown for each).