Project 18

Naltrexone as a long term strategy for heroin addiction: The effects of maternally administered naltrexone on the developing brain

Current standard treatment for heroin addiction involves daily oral administration of methadone, an opiate agonist which maintains the patient in a dependent status. However, the requirement for daily treatment carries the problem of patient non-compliance and, in the case of long term exposure, serious side effects. Naltrexone, an opiate antagonist, has been developed as an alternative treatment to avoid maintaining drug dependency. In addition, a slow release Naltrexone implant has been formulated and is currently used clinically in Perth. Naltrexone implants maintain an addiction-free status for up to 9 months but one of the side-effects is increased fertility and is currently used to treat Polycystic Ovary Syndrome. Naltrexone crosses the placenta and the question addressed in this project is whether maternally administered Naltrexone affects the developing brain. Preliminary evidence in the literature suggests that organ development, including the brain, is accelerated by maternal Naltrexone. Rats will be implanted with a slow release pellet prior to mating. Fetal brain development will be monitored using a variety of measures including detailed weight and volume measures, the extent of myelination, a sensitive marker for brain development, and the expression of opioid receptors.

Publications

Dunlop, S.A., M.A. Archer, J. Quinlivan, L.D. Beazley and J.P. Newnham (1997). Repeated prenatal corticosteroids delay myelination in the ovine central nervous system.J. Maternal-Fetal Medicine. 6, 309-313.