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Sarcoplasmic ionic calcium concentration in neuroleptic malignant syndrome
J R López1, V Sánchez, M J López
1Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas.
Cell Calcium
|May 1, 1989
Summary
Neuroleptic malignant syndrome (NMS), a severe antipsychotic side effect, shows elevated muscle calcium levels. This suggests skeletal muscle dysfunction plays a role in NMS, similar to malignant hyperthermia.
Area of Science:
- Neuroscience
- Pharmacology
- Muscle Physiology
Background:
- Neuroleptic malignant syndrome (NMS) is a rare but severe adverse reaction to antipsychotic drugs.
- Clinical and muscle similarities between NMS and malignant hyperthermia (MH) suggest shared underlying mechanisms.
Purpose of the Study:
- To investigate the role of sarcoplasmic calcium concentration in NMS.
- To compare muscle fiber calcium levels in NMS patients versus healthy controls.
Main Methods:
- Measured resting membrane potential and intracellular calcium ([Ca2+]i) in isolated intercostal muscle fibers from NMS patients and controls using Ca2+ selective microelectrodes.
- Incubated muscle bundles with dantrolene to assess its effect on [Ca2+]i.
Main Results:
- NMS muscle fibers exhibited significantly higher resting sarcoplasmic [Ca2+]i (0.51 microM) compared to controls (0.11 microM).
- Dantrolene reduced [Ca2+]i in both groups, but NMS fibers remained at a higher concentration (0.20 microM vs. 0.06 microM).
Conclusions:
- Skeletal muscle in NMS patients demonstrates altered sarcoplasmic calcium handling.
- This calcium dysregulation in muscle fibers likely contributes to the pathogenesis of NMS.