مقالات پذیرفته شده در هفتمین کنگره بین المللی زیست پزشکی
The effect of exposure to opioids during fetal period on the brain
The effect of exposure to opioids during fetal period on the brain
Shahrzad Ghadirian,1,*
1. Faculty of Sciences, Ferdowsi University, Mashhad, Iran
Introduction: Exposure to opioids in embryonic period is a global phenomenon. Given that pregnancy is a very important period in the life of mother and fetus and central nervous system is one of the first targets of injury in drug abuse, the importance of pregnancy is more obvious. The duration of the exposure, amount and type of substances that enter the blood and central nervous system of the fetus are among the variables that affect the effects of drugs. Just as the amount of absorption by mouth, inhalation, smoking, and injection are not the same, the effects on the vital organs of the fetus and its toxicity are different. Exposure to drugs before birth delays the development of the brain and neural structures during or after birth. The noradrenergic system plays a role in regulating neurological growth during development, which is essential for maintaining normal functioning of the central nervous system. It is also involved in many cognitive processes such as attention and working memory. Therefore, changing norepinephrine levels can lead to deficits in attention. Exposure to opioids in mid-pregnancy to late pregnancy induces long-term, gender-dependent neurochemical changes in the noradrenergic system of male and female adult rats. In male rats, prenatal exposure to opioids increases noradrenaline content and its production and secretion and tyrosine hydroxylase, a key enzyme of catechol amines biosynthesis. These indices decrease in female animals (Alaie et al., 2021).
Methods: The content of this article has been obtained from the study of various books and articles.
Results: Pro encephalin gene expression decreased in male rats exposed to opioids before birth in the pre-visual region and in female rats in the ventral medial nucleus of hypothalamus. Opioids increase dopamine release in several areas of the brain. During development, dopamine acts as a growth regulator and influences neural development. Since dopaminergic system is involved in cognitive processes such as attention, working memory, and inhibitory control, children who have been exposed to methadone before birth are susceptible to attention disorders, obsessive-compulsive behaviors, deficits in executive functions, and it seems that mesolimbic dopaminergic system plays an important role among several neurotransmitter motor skills involved in reward and reinforcement process.
Conclusion: Prenatal exposure to opioids causes a decrease regulation of dopamine receptor expression gene in adult offspring that affects neonatal cognitive development such as memory and learning, attention, language, problem-solving skills and executive activities by damaging the central nervous system of the fetus. Also, studies in rats show that oral administration of morphine by pregnant mother delays development of lateral ventricle and fetal choroid plexus appendix cells. On the other hand، this effect may lead to abnormal function of these cells، namely cerebrospinal fluid secretion and blood supply of brain cells. Any decrease or increase in cerebrospinal fluid by the ependyma cells of the choroid plexus causes abnormalities including hydrocephalus and enlargement of the cerebral ventricles. Considering the effect of maternal addiction on all aspects of children's health and susceptibility to addiction later in life, attention to prevention, treatment and control of substance abuse in pregnancy care is essential.