A Read Headache (06.04.04) –Anger can sometimes get the best of all of us—even if we hold it in. Researchers say suppressing anger may be a cause of chronic headaches.
Eating for Two (04.21.04) - You’re not only what you eat, you may also be what your mother ate while pregnant. A new study raises questions about how nutrition in the womb may affect our health later on.
A man's sex drive in adulthood could be weakened if his mother took aspirin while pregnant. As this ScienCentral News video reports, that’s the suggestion of a new study done in rats.
Researchers at the University of Maryland School of Medicine have found that that a low dose of aspirin or similar painkillers, equivalent to the dose a human would take for a headache, can interfere with the wiring of the developing brain. Male baby rats exposed to aspirin, either in the womb or by nursing, have lower-than-normal sex drives when they grow up.
"The pregnant rat was exposed to aspirin in her water for the last week of pregnancy and the first week of breast-feeding," explains Margaret McCarthy professor of physiology at the University of Maryland School of Medicine. "This is a time of heightened sensitivity of the brain to determine if it's going to become male or female. When we raised those male pups to adulthood, they showed what we would call a mildly impaired sexual behavior."
Scientists have known for a long time that aspirin and other nonsteroidal anti-inflammatory drugs stop pain and inflammation by blocking the body's production of a group of signaling molecules called prostaglandins. But nobody knew that prostaglandins might be involved in regulating sex behaviors.
McCarthy and her colleague Stuart Amateau found that by blocking prostaglandin production, the aspirin actually changed the rats' brain wiring in a region that's also involved in controlling human sex behaviors. They reported their findings in the June 2004 issue of the journal Nature Neuroscience. "Finding the prostaglandin which is normally associated with inflammation responses and fever and pain, etc, that it would have a very highly specific effect on a single brain process...was a very big surprise," says McCarthy.
Michigan State University neuroscientist Marc Breedlove, a pioneer in studies of gender and brain development, agrees. "No one realized that something like aspirin of all things could have an effect like that," says Breedlove, who wrote a commentary on the research in the same issue of Nature Neuroscience. "That's really an interesting and I think important lesson that small changes in the brain early in life can have quite measurable changes in behavior in adulthood."
What does the discovery mean to pregnant women? McCarthy and Breedlove both say there's no reason to panic, but it does lend additional scientific weight to what most women already know—avoid taking any unnecessary drugs while pregnant or nursing.
McCarthy points out that aspirin has a reputation for being safe and harmless, even beneficial. "I think there has been a tendency to think that compounds such as aspirin are pretty innocuous, particularly when we see headlines in the paper that they protect against breast cancer and stroke and heart attack, which in fact they do," she says. "There might be a tendency to think that aspirin is like a vitamin and that it's very good for you. In fact, aspirin is an extremely potent compound that is having effects all over the body in ways that we haven't fully appreciated, as is highlighted by this study."
The scientists plan next to search for the effect in people by looking at a long-term study of thousands of pregnant women and their children that's already going on in England. Until then, McCarthy points out, "it's going to be very hard for us to determine specifically what the effect is in humans, because when a man goes to the doctor and gets a prescription for Viagra, the doctor doesn't ask him, 'Well did your mom take aspirin when she was pregnant with you, 30, 40, maybe 50 yrs ago?'"
"It does make you wonder," agrees Breedlove, "if somewhere right now there's a young husband who's saying to his wife, 'Sorry dear, not tonight, my mother had a headache 30 years ago.'"
McCarthy and Amateau found that one particular prostaglandin interacts with the sex hormone testosterone to masculinize the developing brain. "The brain starts life as neutral and it has the potential to become a male brain or a female brain," McCarthy explains. "The secretion of testosterone by the male testes will result in a male brain and the lack of that exposure will result in a female brain. We've known this for almost 50 years, but we haven't known how this happens."
McCarthy hopes discovering the different chemical pathways that shape male and female brains will lead to an understanding of the very different mental health risks between the genders. "Boys are at much higher risk for autism, dyslexia, early-onset schizophrenia, Tourette Syndrome, and ADD," says McCarthy. "Women are at greater risk for depressive disorder, general anxiety disorder, feeding [disorders], and obsessive compulsive disorder. I say 'boys' vs. 'women' for the very important reason [that] males are at much higher risk for early-onset developmental disorders, whereas females are at much higher risk for late-onset post-pubertal disorders. So by understanding how the brain develops between boys and girls, we're hoping to gain some insight into the relative risk factors that contribute to this difference between the sexes."
Meanwhile, McCarthy recommends that "pregnant women should just continue to try to avoid taking anything that they don't really really need during pregnancy." This research appeared in the June 6, 2004 issue of Nature Neuroscience, and was funded by the National Institute of Mental Health (NIMH).