Covariance of ion flux measurements allows new interpretation ofXenopus laevis oocyte physiology
✍ Scribed by Faszewski, Ellen E. ;Kunkel, Joseph G.
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 193 KB
- Volume
- 290
- Category
- Article
- ISSN
- 0022-104X
- DOI
- 10.1002/jez.1116
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✦ Synopsis
Abstract
An animal‐vegetal net ionic current identified previously using voltage probe techniques in maturing Xenopus laevis oocytes has now been investigated using noninvasive ion‐selective microelectrodes. Three‐dimensional fluxes of hydrogen (H^+^), potassium (K^+^), and bicarbonate (HCO~3~^–^) were characterized with respect to the developmental stage and hemisphere of the oocyte and presence of surrounding follicular tissue. Variable effluxes of H^+^ and HCO~3~^–^ were recorded from both the animal and vegetal hemispheres. Variable influxes and effluxes of K^+^ were also observed. The equatorial region, silent by voltage probe, exhibited fluxes of H^+^ and K^+^. Simultaneous measurement of pairs of ions allowed correlation analysis of two ion types. Notably for H^+^ and K^+^ data, positive and negative correlation at animal and vegetal poles respectively offer an explanation of the unpredictable results obtained when individual ions were observed independently. J. Exp. Zool. 290:652–661, 2001. © 2001 Wiley‐Liss, Inc.