Decreased spontaneous activity in AMPK α2 muscle specific kinase dead mice is not caused by changes in brain dopamine metabolism

AMPK α2 KD mice ran 30% less in daily distance compared to WT. Furthermore, AMPK α2 KD mice showed significantly decreased locomotor activity in the open field test compared to WT when treated with saline or cocaine, respectively, but the increase induced by cocaine was similar in AMPK α2 KD and WT mice. The efflux of dopamine in ventral striatum after cocaine treatment increased similarly by 2.5-fold in the two genotypes, and basal levels of dopamine and its metabolites DOPAC and HVA were also similar between genotypes. These findings show that decreased AMPK activity in muscle leads to decreased voluntary activity which is not due to secondary abnormalities in dopamine levels in the ventral striatum or sensitivity to cocaine. Thus, decreased voluntary activity in AMPK muscle deficient mice is most likely unrelated to regulation of brain dopamine content and metabolism.