Regional catecholamine content in the rat brain: sex differences and correlation with motor activity

Rats were pretreated with α-methyl-p-tyrosine methylester, i.p., 80 $\text{mg}\text{kg}$, every 4 hr for 12hr. At 2, 4, 8 and 12hr of the recovery phase, spontaneous motor activity (SMA), as measured by photocell, and wheel running activity (WRA) were recorded and brain samples taken for assay. α-Methyltyrosine decreased both types of activity and both amines in most brain areas. Overall, SMA was positively correlated with norepinephrine (NE) in midbrain, cerebellum, and cortex and with dopamine (DA) in striatum and midbrain of both males and females. Wheel running activity was positively correlated in females with NE levels in striatum, midbrain and medullapons and with DA levels in striatum and midbrain. Significant differences were noted between male and female controls both in activity and amine levels. The data indicated that females may have a higher utilization rate for NE in the midbrain. The data supports the hypothesis that NE and DA are involved in the central regulation of motor activity.