Influence of physical activity stress and age on the ADCC of lymphocytes from mice

Noradrenaline and its end metabolite 3-methoxy-4-hydroxyphenylglycol inhibit lymphocyte chemotaxis: role of alpha- and beta-adrenoreceptors

The capacity of noradrenaline (NA) and its end metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) to modulate the chemotaxis of lymphocytes from a primary immunocompetent organ (thymus) and a secondary one (spleen) was investigated over a range of concentrations from 10(-12) M to 10(-5) M. Lymphocyte chemotaxis was evaluated in a Boyden chamber. The results indicated that 10(-5) M of NA inhibits the chemotaxis of lymphocytes from both the immunocompetent organs studied, and that this effect is blocked by either propranolol (10(-6) M) or phentolamine (10(-5) M). Similarly, 10(-5) M of MHPG induced a decrease in the chemotaxis capacity of the lymphocytes. In conclusion, high physiological concentrations of NA and its end metabolite modulate the mobility of lymphocytes, and the participation of both alpha and beta adrenoreceptors is necessary, showing a new aspect of neuroimmune interactions.

Exercise-induced stimulation of murine macrophage chemotaxis: role of corticosterone and prolactin as mediators

1. Exercise provokes changes in the immune system, including macrophage activity. Chemotaxis is a necessary function of macrophages if they are to reach the focus of infection and strenuous acute exercise may modulate chemotaxis. However, the precise mechanisms remain unknown. 2. Three experiments were performed in the present study. (1) The effect of strenuous acute exercise (swimming until exhaustion) on the chemotactic capacity of macrophages was evaluated. (2) Peritoneal macrophages from control mice were incubated with plasma from exercised mice or control (no exercise) mice. The differences in the resulting chemotactic capacity were measured. (3) Changes in the concentration of plasma corticosterone and prolactin after exercise were also measured, and the effect of incubation with the post-exercise levels of plasma corticosterone and prolactin on the chemotactic capacity of the peritoneal macrophages was then studied in vitro. 3. Exercise induced an increase in the macrophage chemotaxis index (103 +/- 8 vs. 47 +/- 11 in controls). Incubation with plasma from exercised mice led to an increased level of chemotaxis (68 +/- 18 vs. 40 +/- 6 with plasma from controls). Incubation with concentrations of corticosterone and prolactin similar to those observed in plasma immediately after exercise (corticosterone, 0.72 mumol l-1; prolactin, 88 pmol l-1) raised the chemotactic capacity with respect to that following incubation with the basal concentrations of the hormones in control animals (90 +/- 9 vs. 37 +/- 4 for corticosterone; 72 +/- 9 vs. 41 +/- 4 for prolactin). 4. It is concluded that corticosterone and prolactin may mediate the increased chemotaxis of peritoneal macrophages induced by exercise.

Effect of prolactin on the in vitro phagocytic capacity of macrophages

Prolactin (PRL) plays a modulatory role in immune function. Previous studies have demonstrated that physical activity (swimming until exhaustion) provokes a stimulation in the phagocytic function of peritoneal macrophages. In this study, we have investigated the possible role of PRL as a mediator of physical activity-induced stimulation of macrophage phagocytosis. Peritoneal macrophages from BALB/c mice were incubated for 30 min with 1.1 (basal concentration in these animals), 2.2 (the concentration observed in plasma after swimming until exhaustion) and 8, 16 and 22,000 ng/ml of PRL. The results indicated that incubation of peritoneal macrophages with a concentration of PRL similar to that observed in plasma immediately after physical activity stress stimulates phagocytic capacity. This stimulation was also observed after incubation of macrophages with the higher concentrations of PRL. We conclude that PRL may be considered as a mediator of physical activity-induced stimulation of macrophage phagocytosis, confirming the immunoregulatory role of this hormone.

A study of the role of corticosterone as a mediator in exercise-induced stimulation of murine macrophage phagocytosis

1. It is generally accepted that physical activity provokes changes in the immune system. Previous studies have demonstrated that the stress of physical activity (swimming until exhaustion) increases the phagocytic activity of peritoneal macrophages. However, the precise mechanisms remain unknown. 2. Two experiments were performed in the present study. (A) Peritoneal macrophages from control mice were incubated with plasma from three different groups of mice: (1) mice subjected to swimming until exhaustion with no previous training, (2) mice subjected to the same activity but with 1 month of training (30 min day-1), and (3) a control (non-exercised) group. The differences in the resulting phagocytic (attachment and ingestion) capacity were measured. (B) Changes in the concentration of plasma corticosterone after exercise were also measured, and the effect of incubation with the postexercise plasma corticosterone level on the phagocytic activity of peritoneal macrophages was then studied in vitro. 3. The results were: (A) incubation with plasma from both groups of exercised mice (with and without previous training) led to increased levels of phagocytic capacity (number of C. albicans cells ingested per 100 macrophages). (B) Incubation with a corticosterone concentration of 0.72 mumol l-1 (similar to that observed in plasma immediately after exercise) raised the phagocytic capacity (144 +/- 12 after incubation with 0.72 mumol l-1 vs. 93 +/- 19 after incubation with 0.24 mumol l-1). This increase was also significantly greater than that observed with 7.2 mumol l-1 corticosterone. 4. It is concluded that corticosterone may mediate the increased phagocytic function of peritoneal macrophages induced by exercise.

Effects of physical exercise and aging on ascorbic acid and superoxide anion levels in peritoneal macrophages from mice and guinea pigs

The relationship of physical activity and aging, two processes with a high production of oxygen-free radicals to the ascorbate and superoxide anion (O2-) contents of peritoneal macrophages was studied in two animals species: guinea-pig (in which ascorbic acid is a vitamin) and mouse (in which ascorbic acid is not a vitamin). The effects of exhaustive exercise were examined in young and old animals. The results show that macrophages from old animals have a lower ascorbate content than those from young ones, whereas with exercise the ascorbate content increased in both old and young animals. This increase was higher in young than in old animals, and more evident in mice than in guinea-pigs. Aging also resulted in an increase in the O2- levels of macrophages. With exercise these levels decreased in young mice but increased in young guinea-pigs. In old animals the exhaustive exercise did not change the O2- levels. The results suggest in general a lack of correlation between the intracellular ascorbate and O2- levels in relation to both physical exercise and aging.