Selective noradrenaline depletion markedly alters stress responses in rats

Rats were given FLA-63, followed by R04-1284 0.5 h later to relatively selectively deplete brain NA. After 8 h, some animals were examined for regional brain NA and MHPG-SO4, while some were subjected to 3 h of cold-restraint stress and then examined. All brain regions examined showed significant NA and MHPG reduction. Specific NA depletion markedly exacerbated restraint ulcer formation and plasma corticosterone levels. NA depletion without restraint stress did not induce ulcers or elevate corticosterone. Intact brain NA activity appears to be essential for coping with stress.