Apoptosis may involve in prenatally heroin exposed neurobehavioral teratogenicity?

Heroin abuse during pregnancy is a serious problem worldwide. Among all the illicit drugs, heroin is known as the most commonly abused opioid in the United States and China. Most women addicts are of child-bearing age. Heroin abuse during pregnancy, together with related factors like poor nutrition and inadequate maternal care, has been associated with adverse consequences including developmental delay of the offspring and their neurobehavioral teratogenicity. Researchers have done a lot of work to focus mainly on the variation of neurobehavior and its related factors such as the changes of neurotransmitters, receptors and involvement of the limited brain regions, but no one clearly and comprehensively explain the possible mechanism that may participate in the neurobehavioral teratogenicity induced by prenatal heroin exposure. Studies on animals have shown that heroin is a common neuroteratogen which can produce neurobehavioral defects. There must be some underlying mechanisms in the central nervous system which may take part in these defects. We hypothesized that the alterations in developmental apoptosis during embryogenesis could be one of the possible mechanisms which can cause neurobehavioral teratogenicity in prenatally heroin exposed offspring. Heroin is believed to pass through the placenta and blood-brain barrier much more rapidly than morphine due to the presence of acetyl groups and affects the developing brain. So far, it still remains obscure that whether the apoptosis in a particular brain region induced by heroin exposure in uterus is involved in neurobehavioral teratogenicity. Our hypothesis perhaps provides a more logical and possible explanation of the mechanism responsible for neurobehavioral teratogenicity caused by the prenatal heroin exposure during embryonic development. It can help to develop appropriate experimental animal models to understand the detailed mechanisms involved.