Posts tagged motherhood
Articles and news from the latest research reports.
Does motherhood dampen cocaine’s effects?
Mother rats respond much differently to cocaine than female rats that have never given birth, according to new University of Michigan research that looks at both behavior and brain chemistry.
The findings may help lay the groundwork for more tailored human addiction treatment, based on scientific understanding of how gender, hormones and life experience impact drug use.
In an oral presentation at the Society for Neuroscience meeting, U-M researcher Jennifer Cummings, Ph.D., summarized findings from experiments with rats at the Molecular and Behavioral Neuroscience Institute, part of the U-M Medical School. She worked with Jill Becker, Ph.D., of the U-M Department of Psychology.
They identified clear differences in how intensely the “pleasure centers” in the mother rats’ brains reacted to the drug, compared with non-mothers. Mother rats’ brains released less of a chemical called dopamine, which helps cause the “high” from cocaine.
They also found an interaction with stress: mother rats that were exposed to periods of increased stress weren’t willing to work as hard to get a dose of cocaine, compared with rats that had never given birth or mother rats that weren’t exposed to the stress – even though the stressed mother rats showed an increased tendency to use cocaine when it was easy to get.
Taken together, the findings suggest that the experience of becoming a mother alters a female’s overall response to cocaine – adding complexity to the issue of how best to treat addiction.
“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,” says Cummings, a research investigator at MBNI and former postdoctoral fellow in Becker’s laboratory. “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.”
Chronic Stress During Pregnancy Prevents Brain Benefits of Motherhood
(Credit: Oleg Zabielin / Shutterstock)
A new study in animals shows that chronic stress during pregnancy prevents brain benefits of motherhood, a finding that researchers suggest could increase understanding of postpartum depression.
Rat mothers showed an increase in brain cell connections in regions associated with learning, memory and mood. In contrast, the brains of mother rats that were stressed twice a day throughout pregnancy did not show this increase.
The researchers were specifically interested in dendritic spines – hair-like growths on brain cells that are used to exchange information with other neurons.
Previous animal studies conducted by lead author Benedetta Leuner of Ohio State University showed that an increase of dendritic spines in new mothers’ brains was associated with improved cognitive function on a task that requires behavioral flexibility – in essence, enabling more effective multitasking. The dendritic spines increased by about 20 percent in these brain regions in new mothers, according to her findings.
The stress in this new study negated those brain benefits of motherhood, causing the stressed rats’ brains to match brain characteristics of animals that had no reproductive or maternal experience.
The stressed rats also had less physical interaction with their babies than did unstressed rats, a behavior observed in human mothers who experience postpartum depression.
“Animal mothers in our research that are unstressed show an increase in the number of connections between neurons. Stressed mothers don’t,” said Leuner, assistant professor of psychology and neuroscience at Ohio State and lead author of the study. “We think that makes the stressed mothers more vulnerable. They don’t have the capacity for brain plasticity that the unstressed mothers do, and somehow that’s contributing to their susceptibility to depression.”
(Source: newswise.com)