Jack W. Lipton, PhD, a neuroscientist at Rush-Presbyterian-St. Luke's Medical Center in Chicago, demonstrated that fetal exposure in rats to the drug Ecstasy during a period analogous to the first trimester in humans causes changes in the young rat's brain chemistry and behavior. The study was funded in part by the National Institute on Drug Abuse (NIDA). Ecstasy also is known as MDMA or 3,4-methylenedioxymethamphetamine.
"The limited data that exist suggest that women who use Ecstasy stop taking it when they learn they are pregnant," says Dr. Nora D. Volkow, director of the NIDA. "But many of the animal studies that linked this drug to neurological changes and learning impairments were conducted in situations analogous to the third trimester in humans. Thus, this study sought to investigate a more true-to-life situation by looking at neurobiological changes caused by Ecstasy early in pregnancy."
The researchers injected the drug twice daily from day 14 through day 20 of pregnancy. An equal number of pregnant rats were given sham injections of saline twice daily during the same period as a placebo. The most striking finding was that 21-day-old Ecstasy exposed rats had a 502% increase in the number of dopamine neuron fibers in the frontal cortex as compared to controls. The frontal cortex is important in planning, impulse control and attention.
Similar but smaller increases in dopaminergic fiber density were also evident in the striatum -- an area involved in movement and reward and the nucleus accumbens -- the primary site of action of rewarding stimuli. The investigators believe that this hyperinnervation is either due to MDMA-induced reductions in the normal cell loss that occurs during fetal development, or MDMA-induced increases in chemicals known as trophic factors which can mediate growth and survival of brain cells.
Lipton and his colleagues also found that behavioral changes were evident as well. When 21-day-old rats exposed to Ecstasy in the womb were placed in a new environment away from their littermates, they spent significantly more time exploring and did not habituate as easily to the new environment. Such findings suggest that the Ecstasy exposed rats may have learning or attention deficits or alterations in their anxiety levels. Another possibility is that they are simply hyperactive as a result of their in utero exposure.
"Our findings show that exposing rats to Ecstasy at a time of prenatal development that correlates with the first trimester in humans results in lasting changes in brain chemistry and behavior," notes Lipton. "This research warrants the continued monitoring of children exposed to this drug."
Rush-Presbyterian-St. Luke's Medical Center is an academic medical center that encompasses the 824-bed Presbyterian-St. Luke's Hospital (including Rush Children's Hospital), the 110-bed Johnston R. Bowman Health Center and Rush University. Rush University, with more than 1,270 students, is home to one of the first medical schools in the Midwest, one of the nation's top-ranked nursing colleges, as well as graduate programs in allied health and the basic sciences. Rush is noted for bringing together clinical care and research to address major health problems, including arthritis and orthopedic disorders, cancer, heart disease, mental illness neurological disorders and diseases associated with aging.