B-Endorphin and Natural Killer Cell Cytolytic Activity During Prolonged Exercise. Is There a Connection?

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Authors
  1. Gannon, G.A.
  2. Rhind, S.G.
  3. Suziu, M.
  4. Zamecnik, J.
  5. Sabiston, B.H.
  6. and others
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
This study was designed to test whether a single 50-mg dose of the opioid antagonist naltrexone hydrochloride, ingested 60 min before 2 h of moderate-intensity exercise (i.e., 65% peak 02 consumption), influenced the exercise-induced augmentation of peripheral blood natural killer cell cytolytic activity (NKCA). Ten healthy male subjects were tested on four occasions separated by intervals of at least 14 days. A rested-state control trial was followed by three double-blind exercise trials (placebo (P), naltrexone (N), and indomethacin) arranged according to a random block design. The indomethacin exercise trial is discussed elsewhere (S.G. Rhind, G.A. Gannon, P.N. Skek, and R.J. Shepherd. Med. Sci. Sports Exerc. 30:S20, 1998). For both the P and N trials, plasma levels of Beta-endorphin were increased (P<0.50) at 90 and 120 min of exercise but returned to resting (preexercise) levels 2 h postexercise. CD3(-)CD16(+)CD56(+) NK cell counts and NKCA were significantly (P<0.05) elevated at each 30-min interval of exercise compared with correspondingly timed resting control values. However, there were no differences in NK cell counts or NKCA between P and N trials at any time point during the two trials. Changes in NKCA reflected mainly changes in NK cell count (r = 0.72;P<0.001). TRUNCATED
Keywords
Immune suppression;Natural killer cells;Immune system;Immune function;Immune response;Cell adhesion;Growth hormone;Cortisol;Naltrexone;Natural immunity
Report Number
DCIEM-98-P-38 — Paper
Date of publication
08 Sep 1999
Number of Pages
11
DSTKIM No
99-01456
CANDIS No
511494
Format(s):
Hardcopy;Document Image stored on Optical Disk

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