Linked Life Data

4037111

Source:http://linkedlifedata.com/resource/pubmed/id/4037111

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3 Pt 2
pubmed:dateCreated
1985-10-10
pubmed:abstractText
Buffers are reported to modify electrical function of heart tissue. Since electrophysiological actions of antiarrhythmic drugs are examined in different buffer systems, we set out to examine the influence of buffers on lidocaine's electrophysiological actions by measuring recovery kinetics of maximum upstroke velocity (dV/dtmax) in lidocaine solutions buffered with HCO-3-CO2, N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), and tris(hydroxymethyl)aminomethane (Tris) at extracellular pH 7.4. Transmembrane potential and dV/dtmax were recorded from guinea pig papillary muscle. Recovery kinetics were determined by introducing progressively earlier test stimuli during diastole. During lidocaine (1.5 X 10(-5) M) exposure, the time constant (Tr) of dV/dtmax recovery significantly increased when 21 mM HCO-3-5% CO2 was replaced by either 5 mM HEPES (38 +/- 8%, mean, +/- SED) or 5 mM Tris (41 +/- 6%). This potentiation of Tr was 1) reversed by increasing Tris to 20 mM, and 2) also abolished by restoring HCO-3-CO2 to HEPES or Tris solutions. Decreasing HCO-3 (21-4 mM) and CO2 (5-1%) increased Tr by 27 +/- 1%. We propose that the mechanism for the potentiation of Tr is therefore related to buffer concentration rather than to the lack of HCO-3-CO2. We speculate that, by reducing surface pH, lowered buffer capacity can slow the rate of dV/dtmax recovery.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
249
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H663-71
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1985
pubmed:articleTitle
Influence of buffers on dV/dtmax recovery kinetics with lidocaine in myocardium.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't