In Vitro Potassium Transport in the Mouse Small Intestine
| Autor: | Eiko Inagaki, Koichi Kawamata, Yuichi Suzuki |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Male
Absorption (pharmacology) Physiology Diffusion Membrane Potentials Mice chemistry.chemical_compound Ileum Culture Techniques Intestine Small medicine Animals Forskolin Aldosterone Chemistry Cell Membrane Colforsin Sodium General Medicine Rubidium In vitro Small intestine medicine.anatomical_structure Biochemistry Paracellular transport Potassium Biophysics Adsorption Flux (metabolism) |
| Zdroj: | The Japanese Journal of Physiology. 52:515-520 |
| ISSN: | 0021-521X |
| DOI: | 10.2170/jjphysiol.52.515 |
| Popis: | Ingested K+ is believed to be absorbed mainly in the small intestine by passive diffusion through the paracellular pathway. To further clarify K+ absorption in the small intestine, we determined the unidirectional flux values of Rb+ in vitro by atomic absorption spectroscopy in the mouse ileum mounted in Ussing chambers under short-circuit conditions. The mucosal-to-serosal Rb+ flux (J(ms)) was larger than the serosal-to-mucosal Rb+ flux (J(sm)), resulting in positive net Rb+ absorption (J(net)). The effect of changing the transmucosal potential (V(t)) showed that J(ms) was composed of both a V(t)-dependent diffusion component and a V(t)-independent non-diffusion component, while J(sm) was composed mainly of a V(t)-dependent component. A forskolin treatment eliminated J(net) mainly due to the increase in J(sm). When animals were fed a low-Na diet, J(net) was mainly eliminated as a result of the increase in J(sm). These findings suggest that K+ is absorbed not only by passive diffusion through the paracellular pathway, but also by an active transport mechanism operating through the cellular pathway. In addition, cAMP and aldosterone may be involved in regulating intestinal K+ transport. |
| Databáze: | OpenAIRE |
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