Characterization of volume-sensitive organic osmolyte efflux and anion current in Xenopus oocytes

1997 ◽  
Vol 157 (1) ◽  
pp. 9-16 ◽  
Author(s):  
M. Hand ◽  
R. Morrison ◽  
K. Strange
Keyword(s):  
Xenopus Oocytes ◽  
Organic Osmolyte ◽  
Osmolyte Efflux

Characterization of a novel Kv1.5 channel blocker in Xenopus oocytes, CHO cells, human and rat cardiomyocytes

2001 ◽  
Vol 364 (5) ◽  
pp. 472-478 ◽  
Author(s):  
Alexander Bachmann ◽  
Ilona Gutcher ◽  
Karin Kopp ◽  
Joachim Brendel ◽  
Ralph Bosch ◽  
...  
Keyword(s):  
Cho Cells ◽  
Xenopus Oocytes ◽  
Channel Blocker ◽  
Rat Cardiomyocytes

cAMP-activated C1 conductance is expressed in Xenopus oocytes by injection of shark rectal gland mRNA

1991 ◽  
Vol 260 (3) ◽  
pp. C664-C669 ◽  
Author(s):  
S. K. Sullivan ◽  
K. Swamy ◽  
M. Field
Keyword(s):  
Xenopus Oocytes ◽  
Functional Characterization ◽  
Equilibrium Potential ◽  
Rectal Gland ◽  
Calcium Buffer ◽  
Cl Channel ◽  
Shark Rectal Gland ◽  
Cl Channels ◽  
Cl Conductance

Development of reliable expression systems for use in identification and functional characterization of proteins required for secretory Cl channel activity is key to understanding the molecular basis of cystic fibrosis (CF). Until now, heterologous expression of epithelial Cl channels had not been accomplished. We show here that Xenopus oocytes express an adenosine 3',5'-cyclic monophosphate (cAMP)-activated Cl conductance after injection of mRNA from shark rectal gland. Current through this conductance was rapidly activated by intracellular application of cAMP, reversed near the chloride equilibrium potential (ECl), blocked by the Cl channel inhibitor 5-nitro-2-(3-phenylpropylamino) benzoate, and was not affected by preincubation with the intracellular calcium buffer bis-(2-amino-5-methylphenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester, a condition that prohibits activation of the endogenous Ca-activated Cl conductance.

scholarly journals Functional Characterization of the Arabidopsis Abscisic Acid Transporters NPF4.5 and NPF4.6 in Xenopus Oocytes

2020 ◽  
Vol 11 ◽  
Author(s):  
Sophie Léran ◽  
Mélanie Noguero ◽  
Claire Corratgé-Faillie ◽  
Yann Boursiac ◽  
Chantal Brachet ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Xenopus Oocytes ◽  
Functional Characterization

scholarly journals Calcium Current Activated by Depletion of Calcium Stores in Xenopus Oocytes

1997 ◽  
Vol 109 (6) ◽  
pp. 703-715 ◽  
Author(s):  
Yong Yao ◽  
Roger Y. Tsien
Keyword(s):  
Xenopus Oocytes ◽  
Voltage Dependence ◽  
Calcium Stores ◽  
Kinase C ◽  
Electrode Voltage ◽  
Activation Mechanisms ◽  
Electrophysiological Characterization ◽  
Inwardly Rectifying ◽  
A Current

Ca2+ currents activated by depletion of Ca2+ stores in Xenopus oocytes were studied with a two-electrode voltage clamp. Buffering of cytosolic Ca2+ with EGTA and MeBAPTA abolished ICl(Ca) and unmasked a current in oocytes that was activated by InsP3 or ionomycin in minutes and by thapsigargin or the chelators themselves over hours. At −60 mV in 10 mM extracellular CaCl2, the current was typically around −90 or −160 nA in oocytes loaded with EGTA or MeBAPTA, respectively. This current was judged to be a Ca2+-selective current for the following reasons: (a) it was inwardly rectifying and reversed at membrane potentials usually more positive than +40 mV; (b) it was dependent on extracellular [CaCl2] with Km = 11.5 mM; (c) it was highly selective for Ca2+ against monovalent cations Na+ and K+, because replacing Na+ and K+ by N-methyl-d-glucammonium did not reduce the amplitude or voltage dependence of the current significantly; and (d) Ca2+, Sr2+, and Ba2+ currents had similar instantaneous conductances, but Sr2+ and Ba2+ currents appeared to inactivate more strongly than Ca2+. This Ca2+ current was blocked by metal ions with the following potency sequence: Mg2+ << Ni2+ ≈ Co2+ ≈ Mn2+ < Cd2+ << Zn2+ << La3+. It was also inhibited by niflumic acid, which is commonly used to block ICl(Ca). PMA partially inhibited the Ca2+ current, and this effect was mostly abolished by calphostin C, indicating that the Ca2+ current is sensitive to protein kinase C. These results are the first detailed electrophysiological characterization of depletion-activated Ca2+ current in nondialyzed cells. Because exogenous molecules and channels are easy to introduce into oocytes and the distortions in measuring ICl(Ca) can now be bypassed, oocytes are now a superior system in which to analyze the activation mechanisms of capacitative Ca2+ influx.

scholarly journals Characterization of a Prawn OA/TA Receptor in Xenopus Oocytes Suggests Functional Selectivity between Octopamine and Tyramine

PLoS ONE ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e111314 ◽  
Author(s):  
Sami H. Jezzini ◽  
Dalynés Reyes-Colón ◽  
María A. Sosa
Keyword(s):  
Xenopus Oocytes ◽  
Functional Selectivity
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