2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells
abstract The nematode Caenorhabditis elegans offers significant experimental advantages for defining the genetic basis of diverse biological processes. Genetic and physiological analyses have demonstrated that inositol-1,4,5-trisphosphate (IP 3)–dependent Ca 2 � oscillations in intestinal epithelial...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.282.3805 2023-05-15T17:53:39+02:00 2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells Ana Y. Estevez Olph K. Roberts Kevin Strange Department Of Pharmacology The Pennsylvania State University CiteSeerX Archives application/zip http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.282.3805 en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.282.3805 Metadata may be used without restrictions as long as the oai identifier remains attached to it. ftp://ftp.ncbi.nlm.nih.gov/pub/pmc/5e/23/J_Gen_Physiol_2003_Aug_122(2)_207-223.tar.gz text ftciteseerx 2016-01-07T21:08:08Z abstract The nematode Caenorhabditis elegans offers significant experimental advantages for defining the genetic basis of diverse biological processes. Genetic and physiological analyses have demonstrated that inositol-1,4,5-trisphosphate (IP 3)–dependent Ca 2 � oscillations in intestinal epithelial cells play a central role in regulating the nematode defecation cycle, an ultradian rhythm with a periodicity of 45–50 s. Patch clamp studies combined with behavioral assays and forward and reverse genetic screening would provide a powerful approach for defining the molecular details of oscillatory Ca 2 � signaling. However, electrophysiological characterization of the intestinal epithelium has not been possible because of its relative inaccessibility. We developed primary intestinal epithelial cell cultures that circumvent this problem. Intestinal cells express two highly Ca 2 �-selective, voltage-independent conductances. One conductance, I ORCa, is constitutively active, exhibits strong outward rectification, is 60–70-fold more selective for Ca 2� than Na � , is inhibited by intracellular Mg 2 � with a K 1/2 of 692 �M, and is insensitive to Ca 2 � store depletion. Inhibition of I ORCa with high intracellular Mg 2 � concentrations revealed the presence of a small amplitude conductance that was activated by passive depletion of intracellular Ca 2 � stores. Active depletion of Ca 2 � stores with IP 3 or ionomycin increased the rate of current activation �8- and �22-fold compared with passive store depletion. The store-operated conductance, I SOC, exhibits strong inward rectification, and the channel is highly selective for Ca 2 � over monovalent cations with a divalent cation selectivity sequence of Ca 2 � � Ba 2 � � Sr 2 �. Reversal potentials for I SOC could not Text Orca Unknown |
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abstract The nematode Caenorhabditis elegans offers significant experimental advantages for defining the genetic basis of diverse biological processes. Genetic and physiological analyses have demonstrated that inositol-1,4,5-trisphosphate (IP 3)–dependent Ca 2 � oscillations in intestinal epithelial cells play a central role in regulating the nematode defecation cycle, an ultradian rhythm with a periodicity of 45–50 s. Patch clamp studies combined with behavioral assays and forward and reverse genetic screening would provide a powerful approach for defining the molecular details of oscillatory Ca 2 � signaling. However, electrophysiological characterization of the intestinal epithelium has not been possible because of its relative inaccessibility. We developed primary intestinal epithelial cell cultures that circumvent this problem. Intestinal cells express two highly Ca 2 �-selective, voltage-independent conductances. One conductance, I ORCa, is constitutively active, exhibits strong outward rectification, is 60–70-fold more selective for Ca 2� than Na � , is inhibited by intracellular Mg 2 � with a K 1/2 of 692 �M, and is insensitive to Ca 2 � store depletion. Inhibition of I ORCa with high intracellular Mg 2 � concentrations revealed the presence of a small amplitude conductance that was activated by passive depletion of intracellular Ca 2 � stores. Active depletion of Ca 2 � stores with IP 3 or ionomycin increased the rate of current activation �8- and �22-fold compared with passive store depletion. The store-operated conductance, I SOC, exhibits strong inward rectification, and the channel is highly selective for Ca 2 � over monovalent cations with a divalent cation selectivity sequence of Ca 2 � � Ba 2 � � Sr 2 �. Reversal potentials for I SOC could not |
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Ana Y. Estevez Olph K. Roberts Kevin Strange Department Of Pharmacology |
spellingShingle |
Ana Y. Estevez Olph K. Roberts Kevin Strange Department Of Pharmacology 2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells |
author_facet |
Ana Y. Estevez Olph K. Roberts Kevin Strange Department Of Pharmacology |
author_sort |
Ana Y. Estevez |
title |
2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells |
title_short |
2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells |
title_full |
2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells |
title_fullStr |
2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells |
title_full_unstemmed |
2003. Identification of store-independent and store-operated Ca 2� conductances in Caenorhabditis elegans intestinal epithelial cells |
title_sort |
2003. identification of store-independent and store-operated ca 2� conductances in caenorhabditis elegans intestinal epithelial cells |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.282.3805 |
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Orca |
op_source |
ftp://ftp.ncbi.nlm.nih.gov/pub/pmc/5e/23/J_Gen_Physiol_2003_Aug_122(2)_207-223.tar.gz |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.282.3805 |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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