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|Type:||Artigo de evento|
|Title:||Diurnal Variation Of Plasmatic Melatonin, Corticosterone And Variation Of General Activity In Pigeons Under Light-dark Cycle And Constant Light|
|Author:||Zani de Souza C.M.|
Martins Rosa e Silva A.A.
De Moraes Ferrari E.A.
|Abstract:||This work analyzed the diurnal variation of general activity and plasmatic levels of melatonin and corticosterone in pigeons submitted to a 12:00:12:00h light-dark cycle (lights on at 6:00 a.m.) or to constant light. In both conditions pigeons were observed in 5-min sessions at times 03:00, 06:00, 09:00, 12:00, 15:00, 18:00, 21:00 and 24:00h during two successive days. Behavior was video taped in the home cages for posterior categorization and quantification. Radioimmunoassays were used to evaluate plasmatic levels of melatonin and corticosterone. Blood samples were obtained at the times of behavioral observation. In the light-dark condition the results showed day-night variation of general activity (p < 0.001) and a robust diurnal rhythm of plasmatic melatonin (p < 0.001). Both of these variations as well as the oscillatory secretion of corticosterone disappeared under constant light condition. The parallel changes in general activity and blunting of melatonin rhythm secretion in constant light condition agree with previous evidences that melatonin may regulate behavioral oscillations in the pigeon. The present data are related to the proposition that the timing system in pigeons may involve neuroendocrine relations characterized by interactions between blood born signalization by melatonin and corticosterone.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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