MBL summer researcher Dr. Kimberlei Richardson is currentlyworking to help solve a problem that some 350,000 babies are born witheach year: opiate addiction. Richardson, a neuroscientist andsecond-year postdoctoral fellow in the Pediatrics Department at JohnsHopkins University Hospital, has seen the problem firsthand. Accordingto Dr Richardson, “Baltimore has a high proportion of opiate-exposedinfants. Some of these infants have been exposed to heroin, but amajority of infants are exposed to methadone that the mothers are givento treat the mother’s addiction. Methadone is good for the motherbecause it stabilizes her withdrawal symptoms and ensures that she hasgood prenatal care. But it is a long-acting opiate and thus the infantshave withdrawal symptoms after delivery.”
Opiate withdrawal ininfants, called neonatal abstinence syndrome, is characterized byhigh-pitched crying, inconsolability, increased muscle tone, tremors,vomiting, diarrhea, and, in severe cases, seizures. “The traditionaltreatment for reducing these symptoms in babies is a tincture of opium,a diluted form of morphine. But the optimal therapy is to treat themwith an agent that’s non-addictive,” Richardson says.
Basic andclinical research targeting the cellular and molecular mechanismsunderlying the development of opiate dependence and withdrawal in theinfants are needed. So inside her MBL laboratory, Richardson is usingneonatal rat models to study the role of a neurotransmitter callednorepinephrine (which is released in high amounts during withdrawal)and its influence on specific brain regions believed to be associatedwith opiate withdrawal. “The increased release of norepinephrine is acause of physical withdrawal symptoms,” she says.
Richardson isespecially interested in the effects of a norepinephrine-blocking drugcalled clonidine and its possible use as a treatment for opiate (bothheroin and methadone) exposed infants. The drug, which is traditionallyused for treating high blood pressure, has been shown to relievewithdrawal symptoms in adult humans. It is currently being used for thetreatment of withdrawal symptoms in newborn infants in a randomizeddouble-blind clinical trial by Richardson’s mentor, Dr. Estelle B.Gauda, at Johns Hopkins Hospital (the trial is supported by theNational Institute on Drug Abuse and the National Institutes of Health).
“Theeffects of clonidine on withdrawal symptoms are documented in adultsbut not conclusively in infants,” says Richardson, who hopes to shedlight on the drug’s use as a possible alternative treatment for babiesundergoing withdrawal. “The goal is to extrapolate information fromanimal models, which will ultimately help clinicians decide whichtherapies are best for neonates who display opiate withdrawalsymptoms,” she says.
Dr. Richardson is conducting research at theMBL thanks to a fellowship from the Grass Foundation. This programprovides a first opportunity for neuroscientists during late stages ofpredoctoral training or during postdoctoral years to conductindependent research on their own at the MBL each summer.
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