The skeletal muscle relaxant dantrolene inhibits the release of Ca from the sarcoplasmic reticulum during excitation-contraction coupling and suppresses the uncontrolled Ca release that underlies the skeletal muscle pharmacogenetic disorder malignant hyperthermia; however, the molecular mechanism by which dantrolene selectively affects skeletal muscle Ca regulation remains to be defined. Here w...

The present study demonstrates that human natural killer (NK) cells isolated from peripheral blood of normal individuals are highly sensitive to hyperthermia. The effect was time and dose dependent, and treatment of peripheral blood lymphocytes at 42 degrees for 1 hr almost completely abolished NK activity. The effect was not a consequence of cell death since only a small decrease in cell viabi...