Acute effects of glucocorticoids: behavioral and pharmacological perspectives

There has been evidence since the early eighties that glucocorticoids, apar t from their well known chronic effects, may have acute, short-term effects . However, a lack of understanding of the molecular mechanisms of action ha s hampered appreciation of these observations. Mounting evidence over the y ears has continued to confirm the early observations on a fast corticostero ne control of acute behavioral responses. We summarize experimental data ob tained mainly in rats but also in other species which show: (1) that glucoc orticoid production is sufficiently quick to affect ongoing behavior; (2) t hat there exist molecular mechanisms that could conceivably explain the fas t neuronal effects of glucocorticoids (although these are still insufficien tly understood); (3) that glucocorticoids are able to stimulate a wide vari ety of behaviors within minutes; and (4) that acute glucocorticoid producti on (at least in the case of aggressive behavior) is linked to the achieveme nt of the behavioral goal (winning). The achievement of the behavioral goal reduces glucocorticoid production. It is argued that glucocorticoids are regulatory factors having a well-defi ned behavioral role. Both the acute (stimulatory) effects and the chronic ( inhibitory) effects are adaptive in nature. The acute control of behavior b y corticosterone is a rather unknown process that deserves further investig ation. The pharmacologic importance of the acute glucocorticoid response is that i t may readily affect the action of pharmacologic agents. An interaction bet ween acute glucocorticoid increases and noradrenergic treatments has been s hown in the case of offensive and defensive agonistic behavior. Non-behavio ral data demonstrate that acute increases in glucocorticoids may interfere with other neurotransmitter systems (e.g., with the 5HT system) as well. Th ese observations show the importance of taking into account endocrine backg round and endocrine responsiveness in behavior pharmacological experiments. (C) 1998 Elsevier Science Ltd. All rights reserved.