Exposure to prenatal carbon monoxide and postnatal hyperthermia: short and long-term effects on neurochemicals and neuroglia in the developing brain.
The effects of prenatal exposure to carbon monoxide (CO), a major component of cigarette smoke, was studied alone or in combination with postnatal hyperthermia, on the structural and neurochemical development of the postnatal brain at 1 and 8 weeks. Pregnant guinea pigs (n = 11) were exposed to 200 p.p.m CO for 10 h/day from midgestation until term (68 days), whereas control mothers (n = 10) breathed room air. On postnatal day 4, neonates from the control and CO-exposed pregnancies were exposed to hyperthermia (35 degrees C) for 75 min or remained at ambient (23 degrees C) temperature. Using semiquantitative immunohistochemical techniques the following neurotransmitter alterations were found in the medulla at 1 week: a decrease in met-enkephalin-immunoreactivity (IR) following postnatal hyperthermia and an increase in 5-hydroxytryptamine-IR following a combination of CO and hyperthermia. No alterations were observed in substance P- or tyrosine-hydroxylase-IR in any paradigm. At 8 weeks of age the combination of prenatal CO exposure followed by a brief hyperthermic stress postnatally resulted in lesions throughout the brain and an increase in glial fibrillary acidic protein-IR in the medulla. Such effects on brain development could be of relevance in cardiorespiratory control in the neonate and could have implications for the etiology of Sudden Infant Death Syndrome, where smoking and hyperthermia are major risk factors.
Tolcos
M
M
Department of Anatomy and Cell Biology, The University of Melbourne, Victoria, Parkville, Australia.
Mallard
C
C
McGregor
H
H
Walker
D
D
Rees
S
S
D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology / Q000254:growth & development / Q000473:pathology; D001923:Brain Chemistry / Q000187:drug effects*; D002248:Carbon Monoxide / Q000008:administration & dosage / Q000633:toxicity*; D002540:Cerebral Cortex / Q000187:drug effects / Q000196:embryology / Q000201:enzymology / Q000473:pathology; D004744:Enkephalin, Methionine / Q000378:metabolism; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006168:Guinea Pigs; D006979:Hyperthermia, Induced / Q000009:adverse effects*; D007150:Immunohistochemistry; D019570:Inhalation Exposure; D018811:Maternal Exposure / Q000009:adverse effects; D008526:Medulla Oblongata / Q000187:drug effects / Q000196:embryology / Q000201:enzymology / Q000473:pathology; D009457:Neuroglia / Q000187:drug effects* / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012701:Serotonin / Q000378:metabolism; D013373:Substance P / Q000378:metabolism; D013398:Sudden Infant Death / Q000209:etiology*; D013788:Thalamus / Q000187:drug effects / Q000196:embryology / Q000201:enzymology / Q000473:pathology; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D005904:Glial Fibrillary Acidic Protein; D012701:Serotonin; D013373:Substance P; D004744:Enkephalin, Methionine; D002248:Carbon Monoxide; D014446:Tyrosine 3-Monooxygenase