Differential effects of cocaine on local cerebral glucose utilization in the mouse and in the rat

The aim of the study was to determine whether cocaine causes a different pattern of functional changes in the rat as compared to the mouse. The [(14)C]2-deoxyglucose method, for measuring local cerebral metabolic rates for glucose, was carried out in Sprague-Dawley rats and in two strains of mice, C57BL/6 and DBA/2, following a single intravenous administration of cocaine. Cocaine, according to previous reports, increased glucose utilization in the nucleus accumbens of the rat, while the drug decreased metabolic rates in most of brain areas of both strains of mice. The post-hoc analysis, however, suggests that the pattern of metabolic changes differ in the two strains. In particular, the effect on the shell of the nucleus accumbens was present in the C57, but not in the DBA mice. As the C57 mice are more likely than DBA to initiate cocaine self-administration, the effect on the nucleus accumbens support the role of the mesolimbic pathway in mediating the motivational properties of psychostimulants.