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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
4
|
| pubmed:dateCreated |
1989-5-30
|
| pubmed:abstractText |
The frequency-dependency and voltage-dependency of the suppressing effect of pirmenol, a novel antiarrhythmic agent, on the maximum upstroke velocity (Vmax) of action potentials were examined and compared with those of disopyramide in guinea pig papillary muscles. Pirmenol in concentrations higher than 3 microM decreased Vmax with a slight increase in action potential duration. The reduction of Vmax by pirmenol was enhanced in a frequency-dependent manner over the range of 0.1-2.0 Hz. Pirmenol (30 microM) produced a small resting block (5.5%), whereas disopyramide (100 microM) produced a greater one (25.8%). The onset of frequency-dependent Vmax reduction at 2.0 Hz followed a monoexponential function with a slow rate constant (0.308 +/- 0.055 AP-1). The time constant for the recovery from the frequency-dependent block by pirmenol was also slow (33.5 +/- 5.4 sec), but faster than that of disopyramide (82.5 +/- 12.3 sec). At 1.0 Hz, pirmenol caused a shift (9.5 mV) of the curve relating the resting membrane potential and Vmax along the voltage axis in the hyperpolarizing direction. Thus, pirmenol is a Class Ia drug that has frequency- and voltage-dependent inhibitory actions on Vmax, and its onset and offset kinetics are relatively slow.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Dec
|
| pubmed:issn |
0021-5198
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
48
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
423-34
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
1988
|
| pubmed:articleTitle |
Frequency- and voltage-dependent depression of maximum upstroke velocity of action potentials by pirmenol in guinea pig ventricular muscles.
|
| pubmed:affiliation |
Department of Pharmacology, Hokkaido University School of Medicine, Sapporo, Japan.
|
| pubmed:publicationType |
Journal Article,
In Vitro
|