To the editors:
With regard to the Friday 16 June cover story "The Coke Generation," does author Kitry Krause have any information which documents the effects of cocaine upon the human sperm and egg cells prior to conception? In other words, is there evidence to suggest that cocaine alters the DNA structure of sperm and egg cells?
Debra E. Levie
Kitry Krause replies:
To the best of my knowledge there is not. The following excerpt from "Temporal Patterns of Cocaine Use in Pregnancy" (Journal of the American Medical Association, March 24/31, 1989) by, among others, doctors Ira Chasnoff and Dan Griffith of Northwestern University's perinatal center explains how cocaine may affect fetuses:
"The pharmacologic action of cocaine is consistent with the abnormalities found among the cocaine-exposed infants. Cocaine acts at the nerve terminals to prevent dopamine and norepinephrine reuptake, producing increased circulating levels of these catecholamines. Subsequent vasoconstriction and tachycardia occur. Placental vasoconstriction is marked, decreasing blood flow to the fetus. The fetal hypoxia induced by this vasoconstriction could not only explain the intrauterine growth retardation, but the intermittent vascular disruptions could result in the increased rate of malformations as well.
"In normal human fetal development, norepinephrine, serotonin, and dopamine are among the first neurotransmitters present at early stages of brain development, having been shown to be present in the 3- to 4-month fetus. The protective function of the blood-brain barrier is not well developed in the young fetus; thus, cocaine may act on fetal brain neurotransmitters in the first trimester and induce subtle behavioral changes evident in the newborn infant.
"Cocaine's action in blocking norepinephrine and dopamine reuptake could interfere with some aspects of neuronal development. [V.E.] Grimm has hypothesized that such interference could initiate compensatory neurochemical mechanisms that would partially correct for the abnormalities but still leave the infant impaired in his or her ability to cope with complex environmental demands at some point in later life. The neurodevelopmental deficiencies exhibited by the infants exposed to cocaine in only the first trimester lend credence to this hypothesis."