[Effects of diltiazem on contractility and electromyographic activity of non-fatigued diaphragm in dogs].
BACKGROUND
No data are available for diltiazem on muscle function (contractility and electomyographic activity) of non-fatigued diaphragm.


METHODS
Eighteen pentobarbital-anesthetized dogs were divided into 3 groups of 6 each: Group I received no drug; Group II received small-dose of diltiazem (0.1 mg.kg-1.h-1); Group III received large-dose of diltiazem (0.5 mg.kg-1.h-1). Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi), the difference between esophageal and gastric pressures. Diaphragmatic electromyographic activity (Edi) was measured by means of electrodes placed at the anterior portion of the crural and costal parts of the diaphragm. After measuring baseline values of Pdi and Edi at 20 Hz and 100 Hz stimulation, the study drug was administered for 30 min.


RESULTS
With infusion of diltiazem, Pdi and Edi to each stimulus did not change in Groups II and III. In Group I, these variables also showed no change.


CONCLUSIONS
Diltiazem, at doses below 0.5 mg.kg-1.h-1, does not affect contractility and electromyographic activity of non-fatigued canine diaphragm.
Fujii
Yoshitaka
Y
Department of Anesthesiology, University of Tsukuba Institute of Clinical Medicine, Tsukuba 305-8576.
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003964:Diaphragm / Q000187:drug effects*; D004110:Diltiazem / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004576:Electromyography / Q000187:drug effects*; D009119:Muscle Contraction / Q000187:drug effects*; D018763:Muscle Fatigue
D002121:Calcium Channel Blockers; D004110:Diltiazem