The LA County Department of Public Health notes that cocaine gives one a temporary illusion of enhanced power and energy. However, as the initial elevation of mood fades, depression and other serious medical problems may emerge, including: heart attacks, seizures, and strokes. A cocaine addiction is difficult to overcome; however, a new study may lead to customized drug therapies that can combat addiction in women. The findings were presented by lead author Jennifer Cummings, PhD at the Society for Neuroscience annual meeting in New Orleans on October 15.
Dr. Cummings and her colleagues at the University of Michigan found that having a child may do more than just change a woman’s behavior; her brain chemistry may undergo some distinct changes as well. Dr. Cummings noted that it is known that gender differences exist in the way men and women respond to drugs in the brain. Thus, gender-specific treatments are needed to tailor appropriate treatment methods.
Dr. Cummings notes that an increasing amount of research is focused on studying the physiological and behavioral effects that motherhood can have on women. She explains that research has revealed that hormone changes during pregnancy can actually boost abilities such as memory and the ability to navigate. In order to better understand other chemical changes the brain undergoes during pregnancy and motherhood, the researchers chose to focus on drug response patterns in a rodent model: mother rats versus non-mother rats. They gave the two groups of rats doses of cocaine and found very clear differences in how the “pleasure centers” of their brains reacted. They examined the release of dopamine in the brain because it is the neurotransmitter produces the high that comes with taking drugs. They measured how much of dopamine was released in the ‘pleasure center’ for those who are mothers and those who are not.
Overall the mother rats released far less amounts of dopamine when given cocaine compared to their non-mother counterparts; thus, the drug had less of an effect on the brain. In another experiment examining the behavior of the mother rats, all the rats were given multiple doses of cocaine. Dr. Cummings explained that as more and more doses are given to test subjects, the researchers would expect to see the rats become increasingly active. However, the mother rats did not increase their activity and had much weaker responses.
The researchers designed a series of self-administration experiments to test the rodent’s desire for cocaine after receiving their first dose. They poked holes into the rats’ testing chamber and inserted an intravenous catheter, which would give the rats an immediate dose of cocaine if they poked their nose through the hole. If the rats wanted another dose, they would have to poke their noses through the catheter more and more each time; thus, making them work progressively harder to get the drug. The investigators found some interesting results for this experiment. When they made the rats work harder for the cocaine, the mothers were not as motivated to take the cocaine and tended to discontinue trying for it. However, if they applied some stress them, the mothers took more cocaine compared to the non-maternal rats. Thus, stress appeared to be a strong motivator for cocaine use.
The pregnancy hormones estrogen and progesterone can change the brain structurally and strengthen the neurons, explained Dr. Cummings. She added that this neuroplasticity (the ability of neurons to change) when animals are caring for offspring involves the reorganization of neural circuitry. Now that the researchers have gained some understanding of some of the changes that may occur in a mother’s brain, they hope to further determine the most significant variations that interfere with drug response. The goal is to develop gender-specific drug therapies to combat addiction.
