RESUMO
The effect of 0.03-1.0 µM noradrenaline on the neurogenic response to electrical field stimulation of the juvenile rat tail artery segment in control conditions, after cooling from 36 to 25 degrees C, and after solution pH decrease from 7.4 to 6.6 was studied. Noradrenaline was shown to potentiate neurogenic vasoconstriction diminished by low temperature or low pH. Decrease in neurogenic vasoconstriction being equal, low dose noradrenaline was most effective at low temperature and high dose noradrenaline was most effective at low pH. 1.0 µM noradrenaline was equally effective in both cases. Increase in the neurogenic tone of the rat tail artery evoked by noradrenaline at low temperature and acidosis may contribute to decrease in heat emission at low ambient temperature in vivo.
