Behavioral and neuroendocrine responses controlled by the concerted action of central mineralocorticoid (MRS) and glucocorticoid receptors (GRS).

The balance between MR- and GR-mediated effects is of paramount importance for the homeostatic control of stress responsiveness, adaptation and cognition in animals. If the MR/GR activation ratio is shifted, the control of glucocorticoids on neuronal excitability (Joëls & de Kloet, 1994), neuroendocrine reactivity and behavior will change (de Kloet, 1991). In order to elucidate the underlying neural substrate of behavior, the different levels of biological organization must be brought into relation with each other. For instance, we have suggested that GRs are involved in the storage of information and MRs in the execution of behavior preceding information processing. It is nevertheless important to reemphasize that the biological significance of behavioral responses is due to the concerted action of various receptor systems. In addition, the results on the function of MRs and GRs show clearly that the coupling of one receptor with one function is too reductionistic to fully explain the biological relevance of such receptors.