Abstract
Xenopus oocytes are frequently utilized for in vivo expression of cellular proteins, especially ion channel proteins. A thorough understanding of the endogenous conductances and their regulation is paramount for proper characterization of expressed channel proteins. Here we detail a novel chloride current (I(Cl.swell)) responsive to hypotonicity in Xenopus oocytes using the two-electrode voltage clamp technique. Reducing the extracellular osmolarity by 50% elicited a calcium-independent chloride current having an anion conductivity sequence identical with swelling-induced chloride currents observed in epithelial cells. The hypotonicity-activated current was blocked by chloride channel blockers, trivalent lanthanides, and nucleotides. G- protein, cAMP-PKA, and arachidonic acid signaling cascades were not involved in I(Cl.swell) activation. I(Cl.swell) is distinct from both stretch- activated nonselective cation channels and the calcium-activated chloride current in oocytes and may play a critical role in volume regulation in Xenopus oocytes.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 153-179 |
| Number of pages | 27 |
| Journal | Journal of General Physiology |
| Volume | 103 |
| Issue number | 2 |
| State | Published - Feb 1994 |
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ASJC Scopus subject areas
- Physiology
Cite this
Hypotonicity activates a native chloride current in Xenopus oocytes. / Ackerman, Michael John; Wickman, Kevin D.; Clapham, David E.
In: Journal of General Physiology, Vol. 103, No. 2, 02.1994, p. 153-179.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Hypotonicity activates a native chloride current in Xenopus oocytes
AU - Ackerman, Michael John
AU - Wickman, Kevin D.
AU - Clapham, David E.
PY - 1994/2
Y1 - 1994/2
N2 - Xenopus oocytes are frequently utilized for in vivo expression of cellular proteins, especially ion channel proteins. A thorough understanding of the endogenous conductances and their regulation is paramount for proper characterization of expressed channel proteins. Here we detail a novel chloride current (I(Cl.swell)) responsive to hypotonicity in Xenopus oocytes using the two-electrode voltage clamp technique. Reducing the extracellular osmolarity by 50% elicited a calcium-independent chloride current having an anion conductivity sequence identical with swelling-induced chloride currents observed in epithelial cells. The hypotonicity-activated current was blocked by chloride channel blockers, trivalent lanthanides, and nucleotides. G- protein, cAMP-PKA, and arachidonic acid signaling cascades were not involved in I(Cl.swell) activation. I(Cl.swell) is distinct from both stretch- activated nonselective cation channels and the calcium-activated chloride current in oocytes and may play a critical role in volume regulation in Xenopus oocytes.
AB - Xenopus oocytes are frequently utilized for in vivo expression of cellular proteins, especially ion channel proteins. A thorough understanding of the endogenous conductances and their regulation is paramount for proper characterization of expressed channel proteins. Here we detail a novel chloride current (I(Cl.swell)) responsive to hypotonicity in Xenopus oocytes using the two-electrode voltage clamp technique. Reducing the extracellular osmolarity by 50% elicited a calcium-independent chloride current having an anion conductivity sequence identical with swelling-induced chloride currents observed in epithelial cells. The hypotonicity-activated current was blocked by chloride channel blockers, trivalent lanthanides, and nucleotides. G- protein, cAMP-PKA, and arachidonic acid signaling cascades were not involved in I(Cl.swell) activation. I(Cl.swell) is distinct from both stretch- activated nonselective cation channels and the calcium-activated chloride current in oocytes and may play a critical role in volume regulation in Xenopus oocytes.
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UR - http://www.scopus.com/inward/citedby.url?scp=0027955784&partnerID=8YFLogxK
M3 - Article
C2 - 8189203
AN - SCOPUS:0027955784
VL - 103
SP - 153
EP - 179
JO - Journal of General Physiology
JF - Journal of General Physiology
SN - 0022-1295
IS - 2
ER -