Aging effect on the noradrenaline content of rat brain microvessels.

Microvessels were isolated by sucrose gradient centrifugation and molecular seiving from forebrains of aged and young adult male Sprague-Dawley rats. Determination of noradrenaline levels in preparations obtained from both groups of animals indicated that the level of NA in cerebral microvessels isolated from aged animals (120 /+- 28 pg NA/mg protein) was significantly reduced when compared with the corresponding value from control (young adult) animals (226 /+- 35 pg NA/mg protein). This decrease in NA may indicate a deficiency in the neural control of the microcirculation and predispose to metabolic and functional disturbances of brain tissue.