Changes in catecholamine levels in discrete regions of rat brain during aging.

The effect of aging on the levels of dopamine (DA) in striatum and noradrenaline (NA) in cerebral cortex, cerebellum, hypothalamus, midbrain and pons-medulla from young adult and five groups of aging rats was evaluated. Determinations of the levels of these amines were conducted. Age-related changes which commenced at 12 months were observed in specific brain regions.

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.

The effect of hypoxia on monoamine levels in discrete regions of aged rat brain.

Aged rats were exposed to 10% oxygen for 1, 13, and 36 hr. Norepinephrine levels in cerebral cortex, hypothalamus, hippocampus, midbrain, cerebellum, pons-medulla and dopamine levels in striatum were determined after each exposure. While there was no significant change in monoamine levels in brain regions after 2 hr, norepinephrine concentration in hypothalamus and midbrain decreased significantly after 13 hr of hypoxia.

Metabolism of D, L-3H-norepinephrine in essential hypertension.

Defective control of the cardiovascular system by the sympathetic nerves continues to be incriminated as the potential primary physiologic defect in essential hypertension (EH). The need to measure sympathetic tone has progressed from physiologic mensuration by assessment of reflex and pharmacological responses to the recent assay of norepinephrine (NE) and its congeners in both urine and plasma. The way in which the body handles D,L-B-3H-NE represents yet another technique by which to evaluate sympathetic function.

Post mortem stability of catecholamines in discrete regions of rat brain.

Male Sprague-Dawley rats (200-300 g) were sacrificed by cervical dislocation and left either at room temperature (21-23 degrees C) for periods of 1, 2, and 4 hours or in the refrigerator (4-5 degrees C) for periods of 1, 2, 4, 8, 16, and 24 hours. The brains were left in the intact animals in order to stimulate human autopsy materials. At the end of each period, the rat was decapitated and the brain removed and immediately dissected into the following regions: cerebral cortex, striatum, midbrain, pons and medulla, and cerebellum.