Individual reactivity to novelty predicts probability of amphetamine self-administration

Corticosterone in the range of stress-induced levels possesses reinforcing properties: implications for sensation-seeking behaviors.

“…We have shown in previous studies that HRs and LRs do not differ in the number of nose pokes when no drug is available (7) or in the number of nose pokes in the inactive hole during amphetamine SA (4,8). Similarly, in the present experiments, the two groups did not differ in the number of injections at the 12.5-pug dose or in the number of nose pokes in the inactive hole.…”

“…Higher sensitivity to corticosterone may thus underlie the propensity to seek novel and intense experiences, as well as the higher predisposition to addiction shown by individuals with sensation-seeking personality traits. Indeed, we have previously shown that corticosterone injections facilitate drug-seeking (8) and that HR animals have a longer corticosterone secretion in response to stress (7,8).…”

“…Furthermore, chronic treatment with glucocorticoids can induce either physical or psychological dependence, in the absence of any abnormality in HPA function or reappearance of the disease for which glucocorticoids were administered (15). (iii) HR rats show a longer stress-induced secretion of corticosterone (7,8), the main glucocorticoid in the rat, and corticosterone potentiates the reinforcing properties of drugs of abuse in animals (8).…”

“…Some rats exhibit a high locomotor reactivity when forced to a novel environment (4) or a high preference for novelty when given the choice between a familiar and a novel environment (5). These animals, defined as high responders (HRs) as opposed to low responders (LRs), also show a higher sensitivity to the behavioral and neurochemical effects of psychostimulants (4, 6) and a higher predisposition to self-administer this class of drugs intravenously (4,7,8).To account for the appetitive properties of stressful and stimulating experience, it may be postulated that some of the The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C.…”

Predictors of social status in cynomolgus monkeys (Macaca fascicularis) after group formation

“…In rodents, exposure to a novel environment (e.g., an open field) is often used as an acute stressor [Piazza et al, 1990a, b], and differential patterns and/or levels of locomotion are taken as measures of stress reactivity. In this procedure, rats with high levels of locomotion show larger increases in levels of corticosterone compared to rats with low levels of locomotion, suggesting a differential stress effect [Piazza et al, 1990a]. Similarly, the levels of locomotion induced by administration of a psychomotor stimulant such as cocaine or amphetamine in an open field is sometimes taken as a measure of stress reactivity [Piazza et al, 1990b].…”