Steroid effects on brain functions: an example of the action of glucocorticoids on central dopaminergic and neurotensinergic systems.

It is now clearly established that steroid hormones released from peripheral endocrine glands may, through specific receptors in the brain, directly regulate brain function. These effects may be rapid or involve long-term modifications at the genomic level. Concerning the glucocorticoids, their receptors are found in most neuronal cells, an observation which can be related to their widespread effects on neuronal metabolism. Furthermore, glucocorticoids are often related to stress. We have previously demonstrated that neonatal handling of the rat prevented excessive endocrine response to stress. In adults, this action appeared to protect the animal from potential damaging effects of glucocorticoids and from related impairment of cognitive functions. The effects of glucocorticoids are thought to involve an interaction of several central neurotransmitter systems. One such neurotransmitter is neurotensin, a neuropeptide which was reported to be closely related to central dopaminergic system regulation. This paper presents a rapid overview of the central effects of glucocorticoids and possible evidence for the interrelationship between these steroids, dopamine and neurotensin systems in the regulation of the hypothalamo-pituitary-adrenal axis. It provides a new way to approach stress responses and to develop new substances that may become potential drugs in the treatment of some psychiatric disorders.