Cold restraint alters dopamine metabolism in frontal cortex, nucleus accumbens and neostriatum

The concentrations of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) were assayed in the striatum, nucleus accumbens and frontal cortex of rats following 2 hours of cold restraint. The concentration of DA was significantly decreased in both the striatum (-16%) and nucleus accumbens (-41%) relative to unstressed controls. The content of DOPAC was significantly increased in both striatum (+56%) and frontal cortex (+76%), but not in nucleus accumbens. The DOPAC/DA ratio was increased in all three regions, that in frontal cortex approaching three-fold. These results extend earlier findings of an activation by acute stressors of frontal cortex DA metabolism, but suggest an involvement of other DA systems as well. The finding of the greatest response in frontal cortex, and the previous observations that this was the only region to show significant changes, may be ascribed to the suggested lack of presynaptic autoreceptors in this region.