Abstract |
The myotonia-inducing effects of furosemide and clofibrate, two widely used pharmaceutical agents, were investigated in excised human external intercostal muscle. The effects of anthracene-9-carboxylic acid (9-AC), a well-known myotonia-producing chemical, were also tested for comparison. In the presence of these drugs the electrical threshold was lowered, and a constant current pulse produced multiple spiking. Short trains of direct stimuli were often followed by after-activity, and this caused a myotonia-like prolongation of muscle contraction. Voltage-clamp experiments showed that 0.05 mM anthracene-9-carboxylic acid, 1 mM furosemide, and 1 mM clofibrate decreased the chloride conductance of the muscle fiber membrane to 14, 18, and 40%, respectively, of the normal value, and the myotonia-inducing potency of the 3 drugs was correlated with the decreased chloride conductance. The potassium currents were not affected by these compounds.
|
Authors | H Kwieciński, F Lehmann-Horn, R Rüdel |
Journal | Muscle & nerve
(Muscle Nerve)
Vol. 11
Issue 6
Pg. 576-81
(Jun 1988)
ISSN: 0148-639X [Print] United States |
PMID | 2455224
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
Chemical References |
- Anthracenes
- Chlorides
- Ion Channels
- 9-anthroic acid
- Furosemide
- Clofibrate
|
Topics |
- Anthracenes
(pharmacology)
- Chlorides
(metabolism)
- Clofibrate
(pharmacology)
- Furosemide
(pharmacology)
- Humans
- In Vitro Techniques
- Intercostal Muscles
(drug effects)
- Ion Channels
(drug effects)
- Muscle Contraction
(drug effects)
- Myotonia
(chemically induced)
|