Influence of Neonatal Rearing Conditions on Stress‐Induced Adrenocorticotropin Responses and Norepinepherine Release in the Hypothalamic Paraventricular Nucleus

摘要: Postnatal rearing conditions influence the development of hypothalamic-pituitary-adrenal (HPA) responses to stress in rat. Thus, postnatal handling dampens HPA responsivity stress, while prolonged periods maternal separation have opposite effect. are initiated by release corticotropin-releasing factor and/or arginine vasopressin from neurones paraventricular nucleus hypothalamus (PVNh). A major source input PVNh arises brainstem noradrenergic with signalling occurring via alpha1 adrenoreceptors. We examined response adult animals exposed daily or over first 2 weeks life using microdialysis conscious animals. Maternal increased, greatly decreased and norepinepherine restraint as compared non-handled controls; same pattern was observed for plasma adrenocorticotropic hormone (ACTH) stress. Rearing condition did not affect either alpha2 receptor levels PVNh. However, binding cell body regions locus coeruleus n. tractus solitarius were significantly increased handled These receptors principally located on (i.e. autoreceptors) inhibit noradrenaline at terminal sites. The effects could serve a mechanism differences stress-induced activity among vs early events may differentiation thus alter adulthood.