Abstract:
:A Ca2+-channel blocker derived from funnel-web spider toxin (FTX) has made it possible to define and study the ionic channels responsible for the Ca2+ conductance in mammalian Purkinje cell neurons and the preterminal in squid giant synapse. In cerebellar slices, FTX blocked Ca2+-dependent spikes in Purkinje cells, reduced the spike afterpotential hyperpolarization, and increased the Na+-dependent plateau potential. In the squid giant synapse, FTX blocked synaptic transmission without affecting the presynaptic action potential. Presynaptic voltage-clamp results show blockage of the inward Ca2+ current and of transmitter release. FTX was used to isolate channels from cerebellum and squid optic lobe. The isolated product was incorporated into black lipid membranes and was analyzed by using patch-clamp techniques. The channel from cerebellum exhibited a 10- to 12-pS conductance in 80 mM Ba2+ and 5-8 pS in 100 mM Ca2+ with voltage-dependent open probabilities and kinetics. High Ba2+ concentrations at the cytoplasmic side of the channel increased the average open time from 1 to 3 msec to more than 1 sec. A similar channel was also isolated from squid optic lobe. However, its conductance was higher in Ba2+, and the maximum opening probability was about half of that derived from cerebellar tissue and also was sensitive to high cytoplasmic Ba2+. Both channels were blocked by FTX, Cd2+, and Co2+ but were not blocked by omega-conotoxin or dihydropyridines. These results suggest that one of the main Ca2+ conductances in mammalian neurons and in the squid preterminal represents the activation of a previously undefined class of Ca2+ channel. We propose that it be termed the "P" channel, as it was first described in Purkinje cells.
journal_name
Proc Natl Acad Sci U S Aauthors
Llinás R,Sugimori M,Lin JW,Cherksey Bdoi
10.1073/pnas.86.5.1689subject
Has Abstractpub_date
1989-03-01 00:00:00pages
1689-93issue
5eissn
0027-8424issn
1091-6490journal_volume
86pub_type
杂志文章abstract::The integrase protein of human immunodeficiency virus type 1 is necessary for the stable integration of the viral genome into host DNA. Integrase catalyzes the 3' processing of the linear viral DNA and the subsequent DNA strand transfer reaction that inserts the viral DNA ends into host DNA. Although full-length integ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.92.13.6057
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2010-10-05 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2000-10-10 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 临床试验,杂志文章
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更新日期:2012-01-17 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2014-09-23 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.2007051117
更新日期:2021-01-12 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.79.15.4570
更新日期:1982-08-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2012-02-14 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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doi:10.1073/pnas.1706833114
更新日期:2017-08-22 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2013-08-13 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1973-04-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1993-12-15 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:1996-05-14 00:00:00