Nonselective β blockade attenuates the recruitment of CD62L⁻ T lymphocytes following exercise

Abstract

Exercise induces a selective redistribution of CD62L⁻ T lymphocytes. This study examined the effects of β adrenergic receptor blockade on this phenomenon. Twelve healthy men were exercised to exhaustion on a treadmill prior to and following 1 week of treatment with the nonselective β antagonist propranolol or the ₁ selective antagonist metoprolol. Dynamic exercise resulted in a significant lymphocytosis (p < 0.001). CD8⁺CD62L⁻ T cells showed a greater than 3-fold increase in response to exercise (p < 0.001) as compared to CD8⁺CD62L⁺ T cells, which showed a more modest increase. Treatment with the nonselective β antagonist propranolol significantly attenuated the preferential increase of circulating CD8⁺CD62L⁻ lymphocytes (p = 0.01) but had no effect on CD8⁺CD62L⁺ T cells. Treatment with the ₁ selective antagonist metoprolol did not affect the response of either subset. Our findings replicate a prior study indicating that CD62L expression influences T lymphocyte trafficking in response to exercise and extends those findings by showing that this phenomenon is mediated, in part, via the ₂-adrenergic receptor.