Effects of the calcium antagonist, TMB-8 on halothane and on caffeine contractures of malignant hyperthermia susceptible skeletal muscle.

Abstract

This investigation sought to determine if the Ca2+ antagonist, TMB-8, alters the contracture responses of malignant hyperthermia susceptible (MHS) skeletal muscle to halothane and to caffeine. Muscle fiber bundles were excised from both MHS and normal pigs and exposed to TMB-8 (100 microM), halothane (3%) and caffeine (0.5-8.0 mM), administered alone and in combination. TMB-8 depressed tension developed during isometric twitches in both MHS and normal muscle but had no effect on resting tension (RT). Halothane, however, increased RT in MHS but not in normal muscle. TMB-8 failed to reduce the halothane contracture of MHS muscle but hastened its onset. Caffeine concentrations of greater than or equal to 2 mM increased RT in MHS whereas only 8 mM evoked contracture of normal muscle. These effects were also unaltered by TMB-8. Results suggest that TMB-8 does not inhibit halothane nor caffeine contractures of MHS muscle.

• Authors: J H Williams, M Holland, J C Lee
• Journal: Research communications in chemical pathology and pharmacology (Res Commun Chem Pathol Pharmacol) Vol. 68 Issue 3 Pg. 387-90 (Jun 1990) ISSN: 0034-5164 [Print] United States
• PMID: 2385762 (Publication Type: Journal Article)

Chemical References

• Calcium Channel Blockers
• Caffeine
• 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate
• Gallic Acid
• Halothane

Topics

• Animals
• Caffeine (pharmacology)
• Calcium Channel Blockers (pharmacology)
• Gallic Acid (analogs & derivatives, pharmacology)
• Halothane (pharmacology)
• In Vitro Techniques
• Malignant Hyperthermia (etiology, physiopathology)
• Muscle Contraction (drug effects)
• Swine