Linked Life Data

1383498

Source:http://linkedlifedata.com/resource/pubmed/id/1383498

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
1992-11-23
pubmed:abstractText
1. Smooth muscle cells, enzymatically isolated from the antrum of the guinea-pig stomach, were voltage clamped at room temperature using the whole-cell patch clamp technique. In physiological salt solution (PSS), step depolarization from a holding potential of -90 mV elicited inward calcium current (ICa) followed and superimposed by outward potassium current. 2. Outward current was divided into components depending on the presence of extracellular Ca2+ and others which were not activated as a result of Ca2+ influx. Ca(2+)-dependent components were (1) a fast transient component most likely representing Ca(2+)-activated K+ current (IK(Ca)) immediately triggered by the initial peak of ICa and (2) spontaneous transient outward currents (STOCs) apparently reflecting synchronized opening of IK(Ca) channels by cyclic release of Ca2+ from intracellular stores. Ca2+ influx-independent outward current could be divided into two main components: (1) a transient component (I(to)) showing voltage-dependent activation and inactivation and (2) a non-inactivating component (Ini). 3. I(to) activated with a threshold around -30 mV, was fully available at -90 mV and completely inactivated at -10 mV. The time course of both activation and inactivation of I(to) at different potentials could be described by single exponential functions. Time constants of activation decreased from 35 ms at -10 mV to 10 ms at +40 mV. The time constant of inactivation was about 2 s and only weakly voltage dependent. Time constants for exponentially developing recovery from inactivation of I(to) ranged from 0.1 s at -100 mV to 10 s at -30 mV. I(to) was insensitive to 4-aminopyridine (4-AP, 5 mmol/l), slightly sensitive to tetraethylammonium (TEA, 10 mmol/l), but substantially inhibited by caffeine (10 mmol/l) and Cd2+ (5 mmol/l). Estimates of the single-channel conductance by current fluctuation analysis indicated a small value of about 2.5 pS. 4. The action of TEA on current elicited from a holding potential of -10 mV indicated a major contribution to Ini of a distinct component (Ini,K) that was completely blocked by this substance at a concentration of 10 mmol/l. Ini was almost unaffected by 4-AP (5 mmol/l) and caffeine (10 mmol/l), but strongly suppressed by Cd2+ (5 mmol/l). Current fluctuation analysis of Ini,K gave a value for the single-channel conductance of about 60 pS. 5. Ca2+ inward current was studied in PSS ([Ca2+]o = 2.5 mmol/l) using pipette solution in which K+ was replaced by Cs+ to suppress outward K+ currents.(ABSTRACT TRUNCATED AT 400 WORDS)
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-1698983, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-1700105, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-1886057, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2213601, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2399118, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2409600, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2415914, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2417191, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2422353, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2427250, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2428252, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2436142, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2436483, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2439228, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2441034, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2442353, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2443653, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2451807, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2475611, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2482352, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2539433, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2580269, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2600838, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2600861, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2621620, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2703823, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-2819818, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-3601643, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-4546555, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-5063524, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-5461324, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-6270629, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-6310100, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-6787566, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-68708, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-7326323, http://linkedlifedata.com/resource/pubmed/commentcorrection/1383498-7326324
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0022-3751
pubmed:author
pubmed:issnType
Print
pubmed:volume
451
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
387-417
pubmed:dateRevised
2010-9-7
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Characterization of membrane currents in single smooth muscle cells from the guinea-pig gastric antrum.
pubmed:affiliation
Department of Physiology, Philipps University, Marburg, FRG.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't