Beta-adrenergic receptors in lymphocyte subsets after exercise. Alterations in normal individuals and patients with congestive heart failure.

Abstract

Dynamic exercise increases the number of j-adrenergic receptors in mixed lymphocytes by a mechanism that is incompletely understood. In a set of in vivo studies, we have investigated the effects of dynamic exercise on the subset distribution of circulating lymphocytes and on the number of fJ-adrenergic receptors in each of these subsets in two groups of patients. In healthy subjects, exercise increased plasma norepinephrine and epinephrine and caused lymphocytosis. Whereas the number of The,lper cells increased only modestly, the number of Tsuppressoricytotoxic and natural killer cells more than tripled. The number of f-adrenergic receptors varied among subsets but was not significantly altered by dynamic exercise in any subset except natural killer cells (35% increase, p=0.0302). In a group of patients with congestive heart failure, dynamic exercise increased plasma norepinephrine but did not alter plasma epinephrine and did not cause significant lymphocytosis. We did not detect any significant alterations of circulating leukocyte subsets or /3-adrenergic receptors in any of these subsets after exercise. A combined analysis of healthy patients and heart failure patients revealed a significant correlation between increases in plasma epinephrine and increases in circulating lymphocytes. We conclude that the exercise-induced increase in /8-adrenergic receptors of mixed lymphocytes is predominantly caused by a redistribution of circulating cell subsets that differ in their 3-adrenergic receptor number. This appears to be mediated by epinephrine rather than norepinephrine. (Circulation 1990;82:2003-2010 It is well documented that prolonged exposure to agonists decreases the number of /3-adrenergic receptors in cultured cells and solid tissues of animals and humans in vitro and in ViVO.1-3 Such downregulation also occurs in human lymphocytes after prolonged treatment with 13-adrenergic agonists.

Exercise-induced changes in β-adrenergic-receptor mRNA level measured by competitive RT-PCR

“…They also found no significant alteration in the number of b-ARs in subsets other than natural killer cells after exercise, suggesting that the exercise-induced increase in b-AR of mixed lymphocytes is caused largely by redistribution of circulating cell subsets that differ in b-AR number. They also reported that the observed redistribution of circulating subsets alone can only explain an apparent increase in b-AR of 19% in mixed lymphocytes (23). In general, maximal exercise induces a near doubling of lymphocytic b-ARs, as found in the present study.…”

“…Maisel et al (23) pointed out that a change in lymphocytic subset composition contributes to the increase in number of lymphocytic b-ARs. They demonstrated that dynamic exercise markedly increases the number of T suppressor/cytotoxic and natural killer cells but only modestly increases the number of T helper cells; T helper cells have few b-ARs, whereas T suppressor/cytotoxic and natural killer cells have a high b-AR content.…”

Epinephrine promotes pulmonary angiitis: evidence for a β1-adrenoreceptor-mediated mechanism

“…Lymphoid cells express ␤-AR, and both T and NK lymphocytes express ␤ 2 -AR. Maisel and colleagues (17) have suggested that ␤ 2 -AR density differs among leukocytes with NK cells Ͼ CD14 monocytes Ͼ T cytotoxic cells Ͼ Th cells. Sanders and coworkers (23) have demonstrated that unlike Th1 lymphocytes, Th2 lymphocytes do not express ␤ 2 -AR.…”

Neonates born to pre-eclamptic mothers have a higher percentage of natural killer cells (CD3 - /CD56+16+) in umbilical cord blood than those without pre-eclampsia

“…Psychological 49 and physiological stressors are known to result in a significant redistribution of the lymphocyte population and increase the percentage of NK cells 50,51 in adult peripheral blood, probably through activation of the sympathetic nervous system 52,53 and/or the hypothalamic-pituitaryadrenal axis 54 . This phenomenon is mediated, in part, by 55 , including NK cells 56 . Pre-eclampsia could be considered a state of physiological stress for the fetus resulting from chronic uteroplacental deficiency, and this may partially explain the higher percentage of NK cells observed in neonates of pre-eclamptic mothers.…”