Nerve growth factor brain concentration and stress: changes depend on typeof stressor and age

In the relationship between the hippocampus and the hypothalamo-pituitary-a drenocortical axis; trophic and tropic actions of nerve growth factor are i nvolved in parallel with those on the cholinergic nuclei of the basal foreb rain. Here, we report the changes produced by stress activation of the hypo thalamo-pituitary-adrenocortical axis on hippocampal and basal forebrain ne rve growth factor concentrations in 3-month-old male Wistar rats. The stres sors used were: restraint; cold exposure: footshock; and rotatory platform. Restraint stress tended to reduce nerve growth factor in the hippocampus a nd reduced it significantly in the basal forebrain. Nerve growth factor lev els in the hippocampus were not modified by cold exposure. However, a singl e unrepeated exposure significantly increased nerve growth factor in the ba sal forebrain. Both acute and chronic foot-shock reduced nerve growth facto r in the hippocampus. leaving the levels in the basal forebrain unmodified. Acute but not chronic rotatory platform reduced nerve growth factor in the hippocampus, while showing a tendency, more pronounced after chronic appli cation, toward an increase in the basal forebrain. Since with aging both ac tivity of the hypothalamus-pituitary-adrenal axis and nerve growth factor t rophic and tropic functions change, we studied the effect of restraint and cold stress in the 24-month-old male rat. The variations in nerve growth fa ctor concentrations in the basal forebrain following stress activation are no longer present in the aged rat. The picture that emerges is indicative o f a complex relationship between stress and nerve growth factor which is in fluenced by the kind of stressor and by age. Lack of uniformity in the effe cts produced by different stressors might reside in different qualitative a nd/or quantitative degree of involvement of neurotransmitters and/or neuroh ormones for each of them. (C) 2000 ISDN. Published by Elsevier Science Ltd. All rights reserved.