Greater dissemination and implementation of effective interventions to reduce alcohol use and increase physical activity in cancer patients are recommended.
We have shown that repeated administration of cocaine, as well as other drugs and nondrug stressors, can induce alternating increases and decreases in several neurotransmitter and endocrine endpoints, which we call oscillation. Oscillation studies have typically used 3-4 pretreatments with cocaine or other agents, raising the question of whether oscillation lasts beyond this point. Using plasma corticosterone as our endpoint measure, we therefore inquired whether oscillation would persist across eight administrations of cocaine over a 28-day period. We report oscillation of corticosterone levels persisting across all eight cocaine groups. Our data also indicate that the degree of oscillation increases with the intertreatment interval.
In this study, we investigated the immune alterations induced in rats by an aversive conditioned stimulus that had been developed through pairings with electric shock. The results showed that the conditioned stimulus induced a pronounced suppression of the mitogenic responsiveness of splenic and blood lymphocytes and a reduction in splenic natural killer cell activity. In contrast, the conditioned stimulus did not induce any alteration in the mitogenic responsiveness oflymphocytes from the mesenteric lymph nodes. The reduction in the mitogenic responsiveness of splenic lymphocytes was not related to a reduction in the level of interleukin-2 GL-2) production, as splenic lymphocytes from subjects exposed to the conditioned stimulus showed normal levels of IL-2. Plasma corticosterone measurements showed that glucocorticoid secretion was related to the alteration of the mitogenic responsiveness of blood lymphocytes. However, plasma corticosterone levels were not related to any of the other immune measures. These findings establish that a signal for an aversive event can have a pronounced effect on immune function, but that such an effect is dependent on the particular compartment of the immune system studied. These results support the claim that glucocorticoids can induce immune alterations, but they suggest that additional pathways must be involved in the immune alterations induced by a conditioned aversive stimulus.
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