| Autor: |
Gunter-Smith, Pamela J., Grasset, Etienne, Schultz, Stanley G. |
| Zdroj: |
Journal of Membrane Biology; December 1982, Vol. 66 Issue: 1 p25-39, 15p |
| Abstrakt: |
Summary Necturus small intestine actively absorbs sugars and amino acids by Na-coupled mechanisms that result in increases in the transepithelial electrical potential difference (?ms) and the short-circuit current (Isc) which can be attributed entirely to an increase in the rate of active Na absorption. Studies employing conventional microelectrodes indicate that the addition of alanine or galactose to the mucosal solution is followed by a biphasic response. Initially, there is a rapid depolarization of the electrical potential difference across the apical membrane (?ms) which reverses polarity (i.e. cell interior becomes positive with respect to the mucosal solution) and a marked decrease in the ratio of the effective resistance of the mucosal membrane to that of the serosal membrane (Rm/Rs); these events do not appear to be dependent on the availability of metabolic energy. These initial, rapid events are followed by a slow increase in (Rm/Rs) toward control values which is paralleled by a repolarization of?ms and increases in?ms andIsc; this slow series of events is dependent upon the availability of metabolic energy. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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