[Effects of activation of kappa-opioid receptors on the behavior at the postnatal development of the stress reactivity systems].

It is known that stress changes state and reactivity of humoral systems of stress, particularly the hypothalamic-pituitary-adrenal system (HPA) and the dynorphin-K-opioid system (DKOS) in any age periods, including ones of early postnatal development. Supposedly these changes are underlying some disorders. Difference in state and reactivity of the HPA system is well established. But the role of DKOS is not clear. Further study of this requires summarizing of the literature data on physiology of DKOS activation and ethological features of the activation in different periods of postnatal development. It is possible to conclude that the mode of reaction to stimulation of the DKOS differs in the early development in contrast to adult animals. The mode of reaction can be changed in relation to the periods of development of the system of stress-reactivity and can depend on prior activation of the stress system in a particular period.