Adrenaline, noradrenaline and dopamine levels in specific brain stem areas of acutely immobilized rats.

Catecholamines (adrenaline, noradrenaline and dopamine) have been measured in specific areas of the rat brain stem after acute immobilization stress. Adrenaline levels were significantly decreased after 240 min of immobilization in all areas studied: A1 area, nucleus commissuralis (NCO), A2 area, anterior part of the nucleus tractus solitarii (NTS), and the locus coeruleus. Noradrenaline concentrations in stressed rats were significantly reduced only in the NTS area. In contrast, during stress there were no significant changes in dopamine concentrations with respect to control values in any of the areas studied. These results implicate the participation of central adrenaline neurons, localized in specific brain stem areas, and noradrenaline neurons innervating the rostral part of the nucleus tractus solitarii, in the mechanism of central response to acute stress.