Effects of Nicotine on Brain Development
Abstracts
Initial Award Abstract |
|
Maternal cigarette smoking produces profound health effects including premature labor, low birth weight, stillbirth, and neonatal death. Postnatal growth and behavior also are affected. For example, several researchers have reported a possible association between hyperactivity in children and exposure to nicotine, due to maternal cigarette smoking. Despite all the public health warnings, some 25% of pregnant women still smoke. Many who agree to quit smoking are placed on nicotine replacement therapies such as the patch. Nicotine is well known as an important component of cigarette smoke and has been implicated in many of the adverse effects of smoking, on fetal development. A few animal studies support the notion that many effects of cigarette smoking on the brain are due to nicotine and/or its metabolite(s). Thus, chronic exposure to nicotine via the patch might be even more detrimental than smoking to some aspects of brain development. We use a relatively new imaging procedure called proton magnetic resonance spectroscopy ('H-MRS), which can be performed safely on humans. With this technology, we have shown that chronic exposure to nicotine in rats (using a procedure similar to that of the patch) produces long-term effects on the brain. We propose to study this issue further.
Although data clearly show that prenatal exposure to nicotine can be harmful, considerably less is known about the effects of nicotine on the brain during other developmental periods, particularly during puberty. The brain is still maturing rapidly during puberty and, most likely, remains vulnerable to the detrimental effects of nicotine during this period as well. We propose to extend our studies to determine if the "window" of vulnerability that exists during very early development extends into adolescence. |
Final Report |
|
Maternal cigarette smoking produces profound health effects including premature labor, low
birth weight, stillbirth, and neonatal death. Postnatal growth and behavior also are affected. Despite
all the public health warnings many pregnant women still smoke or are placed on nicotine
replacement therapies such as the patch. Nicotine is well known as an important component of
cigarette smoke and has been implicated in many of the adverse effects of smoking, on fetal
development. Although data clearly show that prenatal exposure to nicotine is bad, considerably less
is known about the effects of nicotine on the brain during other developmental periods, particularly
during puberty. The brain is still maturing rapidly during puberty and, most likely; it remains
vulnerable to the detrimental effects of nicotine during this period as well. We extended our studies to
determine if the "window" of vulnerability that exists during very early development extends into
adolescence. We used a relatively new imaging procedure called proton magnetic resonance
spectroscopy (1 H MRS), which can be performed safely on humans. One of the brain metabolites
measured by 1 H MRS is the compound n-acetyl-aspartate (NAA). In animals with brain damage or
humans with neurodegenerative diseases, NAA concentrations are reduced, in a regionally specific
manner. The concentration of this brain metabolite reflects the health and viability of neurons. We
hypothesized that developmental nicotine exposure would result in a decrease in NAA
concentrations. Our data indicated that NAA concentrations were not reduced in adult offspring
exposed to nicotine during development, however other brain metabolites were affected. The primary
focus of the study (long-term effects of developmental nicotine exposure) has been completed and
written up as the Ph.D. dissertation for Christine Cloak. We are in the process of converting the
dissertation into journal, articles for publication. Tissue has been collected but not yet analyzed for the
progressive developmental effects of nicotine exposure (early developmental time points). Although
our hypotheses concerning the long-term effects of nicotine during development on NAA
concentrations in the brain were not supported, other measurable metabolites were effected such as
glutamate and myo-inositol. Future studies will focus more on these metabolites. |
Publications
| Effects on peripuberal nicotine exposure on the brain as detected by 1H-MRS |
| Periodical: Society for Neuroscience Abstracts |
Index Medicus: |
| Authors: Cloak CC, Poland RE |
ABS |
| Yr: 2000 |
Vol: |
Nbr: |
Abs: 589 |
Pg: |
| Effects on peripuberal nicotine exposure on the brain as detected by 1H-MRS |
| Periodical: Society for Neuroscience Abstracts |
Index Medicus: |
| Authors: Cloak CC, Poland RE |
ABS |
| Yr: 2000 |
Vol: |
Nbr: |
Abs: 589 |
Pg: |
