Central renin-angiotensin system in stress adaptation and hypertension

The dynamic regulation of neurotransmitters and their receptors is an impor tant component of the process of coping and stress adaptation. Among the ce ntral neurochemical systems, CRF and the renin-angiotensin may represent ma jor modulatory systems involved in the adaptation of an organism to chronic stress, balancing the response demands that the stressor places an the cen tral nervous system with the potentially detrimental effects that a sustain ed stress response may produce. As such, the study of these two systems wit h respect to their neurotransmitters and receptors will allow us to achieve a better perspective on the mechanisms responsible for effective short-ter m coping with stress as well as long-term adaptation and restoration in res ponse to chronic or repeated stress. It will then be possible to verify the level of activation of different components of the central pathways involv ed in the mediation of stress responses in rat strains which develop hypert ension following chronic exposure to stress. The primary objective of the present paper is to review some facts on the c ontribution of the central renin-angiotensin system on the regulatory mecha nisms involved in the mediation of physiological responses to stress and on the involvement of these neurons in the CNS adaptation in rat strains that are;developing hypertension when chronically exposed to stress. Neurons th at are expressing angiotensin-receptors may be important in the short-term adaptation to stress by potentiating sympathoadrenal and/or hypophyso-pitui tary-adrenal responses. These same neurons may also participate in long-ter m. Stress-adaptation by altering gene expression of their angiotensin recep tors. Moreover, these processes represent potential paints of dysregulation in the case of extreme, repeated or prolonged stress, and thus in the deve lopment of stress-related pathological states such as hypertension and hear t diseases.