February 1, 1992AJP Cell Physiology

Excitation-contraction coupling in pigs heterozygous for malignant hyperthermia

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Population

Bundles of intact muscle cells dissected from pigs of various genotypes

Comparison

Caffeine or surface membrane depolarization vs Comparison among genotypes

Design

Preclinical

Authors

EGEsther M. GallantAustralian National University LLLinnea LentzMedtronic (Ireland)

Discussion

Member takes

Implication

Intermediate caffeine sensitivity in heterozygous MHS models warrants no change in carrier screening; leaves open whether altered T-tubule–SR coupling drives human MH risk.

Structured PICO

Population

Bundles of intact muscle cells dissected from pigs of various genotypes (homozygous malignant hyperthermia-susceptible [MHS], heterozygous, and homozygous normal)

Intervention

Caffeine (direct stimulation of the SR) or surface membrane (sarcolemma) depolarization (electrical stimuli or elevated extracellular potassium)

Comparator

Comparison among genotypes (MHS, heterozygous, and normal)

Outcome

Contractile responses (caffeine threshold for contractures, control twitch tension, potassium-induced contractures)surrogate

Heterozygous malignant hyperthermia pigs exhibit intermediate caffeine thresholds but enhanced force production via sarcolemmal depolarization similar to homozygous MHS pigs, suggesting altered transverse tubule to SR signal transduction.

Cite This Study

Gallant et al. (1992) studied this question.

synapsesocial.com/papers/6a70443db27f15817827465f https://doi.org/10.1152/ajpcell.1992.262.2.c422

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Implication

Intermediate caffeine sensitivity in heterozygous MHS models warrants no change in carrier screening; leaves open whether altered T-tubule–SR coupling drives human MH risk.