According to a recent cocaine study performed on rat mothers, becoming a mother changes a female rat’s response to cocaine, lessening the drug’s effects on the animal’s body. The study was performed by a University of Michigan team of scientists led by Jennifer Cummings. The team concluded their evidence by feeding cocaine to female rats, some of which were mothers and some of which were not mothers. Later, they examined the release of dopamine in the “pleasure center” of the rats’ brains. Mother rats released much less dopamine when they were fed cocaine than rats who did not have babies.
In a separate experiment, all of the rats were administered multiple cocaine dosages. Researchers observed the animals to see if they became more active, as was expected. They discovered that the mother rats did not increase their activity, while the non-mother rats did.
Cummings asserts, “While we have not yet identified a mechanism to explain these differences, they do suggest that the reward system and brain circuitry affected by cocaine is changed with maternal experience. The next step is to determine how factors such as hormone changes in pregnancy and early motherhood, and the experience of caring for offspring, might be differentially contributing to this response.”
Cummings presented her findings last week at the Society for Neuroscience Conference.