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Fig. 7 | Molecular Brain

Fig. 7

From: Electrophysiological behavior of neonatal astrocytes in hippocampal stratum radiatum

Fig. 7

Neonatal astrocytes exhibit a deficient K+ uptake capacity. a, b The V M responses from a neonatal and mature astrocyte as indicated. To test K+ uptake capacity, the K+ ions in the electrode were replaced fully by Na+ ions, whereas the bath K+ remained at the physiological 3.5 mM. A negative holding current (I holding) was applied at incremental duration from 1 to 5 s to shift the V M downward to −75 mV. In between the I holding pulses, the cell was maintained at I holding = 0 for V M recovery back to the resting levels. The longer the duration of the I holding pulses, the larger the induced maximal V M hyperpolarization. Also, the longer the duration of I holding pulse, the more negative of the V rev s, indicating more accumulation of K+ inside astrocytes (see c and d in expanded scale). The V rev deviated much less from the resting V M in neonatal astrocytes compared to mature astrocytes. e According to GHK equation, the estimated intracellular K+ concentrations, corresponding to the V rev values, are plotted against the I holding pulse durations for neonatal and mature astrocytes as indicated by color codes. Overall, the capacity of K+ uptake in neonatal astrocytes is ~50 % less than mature astrocytes

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