Data/hora: 02/06/2024 14:58:21

Provedor de dados: | Brazilian Journal of Medical and Biological Research
País: | Brazil
Título: | Effects of stress on catecholamine stores in central and peripheral tissues of long-term socially isolated rats
Autores: | Dronjak,S.; Gavrilovic,L.
Data: | 2006-06-01
Ano: | 2006
Palavras-chave: | Cold stress; Immobilization stress; Catecholamines; Hypothalamus; Hippocampus; Adrenal glands.
Resumo: | Both the peripheral sympatho-adrenomedullary and central catecholaminergic systems are activated by various psycho-social and physical stressors. Catecholamine stores in the hypothalamus, hippocampus, adrenal glands, and heart auricles of long-term socially isolated (21 days) and control 3-month-old male Wistar rats, as well as their response to immobilization of all 4 limbs and head fixed for 2 h and cold stress (4ºC, 2 h), were studied. A simultaneous single isotope radioenzymatic assay based on the conversion of catecholamines to the corresponding O-methylated derivatives by catechol-O-methyl-transferase in the presence of S-adenosyl-l-(³H-methyl)-methionine was used. The O-methylated derivatives were oxidized to ³H-vanilline and the radioactivity measured. Social isolation produced depletion of hypothalamic norepinephrine (about 18%) and hippocampal dopamine (about 20%) stores and no changes in peripheral tissues. Immobilization decreased catecholamine stores (approximately 39%) in central and peripheral tissues of control animals. However, in socially isolated rats, these reductions were observed only in the hippocampus and peripheral tissues. Cold did not affect hypothalamic catecholamine stores but reduced hippocampal dopamine (about 20%) as well as norepinephrine stores in peripheral tissues both in control and socially isolated rats, while epinephrine levels were unchanged. Thus, immobilization was more efficient in reducing catecholamine stores in control and chronically isolated rats compared to cold stress. The differences in rearing conditions appear to influence the response of adult animals to additional stress. In addition, the influence of previous exposure to a stressor on catecholaminergic activity in the brainstem depends on both the particular catecholaminergic area studied and the properties of additional acute stress. Therefore, the sensitivity of the catecholaminergic system to habituation appears to be tissue-specific.
Tipo: | Info:eu-repo/semantics/article
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000600011
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X2006000600011
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.39 n.6 2006
Fonte: | info:eu-repo/semantics/openAccess