Mechanisms of pH recovery from intracellular acid loads in the leech connective glial cell
✍ Scribed by Marek Szatkowski; Wolf-Rüdiger Schlue
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 860 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0894-1491
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✦ Synopsis
We used double-barrelled, neutral carrier, pH-sensitive microelectrodes to study the mechanisms by which the intracellular pH (pHJ is regulated in the connective glial cells of the medicinal leech. In HEPES-buffered, nominally C02/HCO;-free solutions the recovery of pHi from intracellular acidosis is Na+-dependent and reduced by at least half in the presence of amiloride, suggesting the action of Na':H+ exchange. The rate of pHi recovery by this mechanism can be increased by raising the extracellular buffering power or by increasing extracellular pH. The presence of COflCO, greatly increases the rate of pHi recovery from intracellular acidosis. This COJHC0,stimulated recovery is also dependent on external Na' , largely C1--independent, inhibited by DIDS, and accompanied by membrane hyperpolarization. This is consistent with it being mediated by the electrogenic cotransport of Na' and HCO, into the cells. A Cl--dependent component to Na+-and HCO; -dependent regulation is most easily explained by the added presence of a Na+-dependent exchange of HCO, and C1-. ~~~