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Neonatal nicotine exposure impairs nicotinic enhancement of central auditory processing and auditory learning in adult rats.
- Source :
-
The European journal of neuroscience [Eur J Neurosci] 2006 Aug; Vol. 24 (3), pp. 857-66. Date of Electronic Publication: 2006 Jul 18. - Publication Year :
- 2006
-
Abstract
- Children of women who smoke cigarettes during pregnancy display cognitive deficits in the auditory-verbal domain. Clinical studies have implicated developmental exposure to nicotine, the main psychoactive ingredient of tobacco, as a probable cause of subsequent auditory deficits. To test for a causal link, we have developed an animal model to determine how neonatal nicotine exposure affects adult auditory function. In adult control rats, nicotine administered systemically (0.7 mg/kg, s.c.) enhanced the sensitivity to sound of neural responses recorded in primary auditory cortex. The effect was strongest in cortical layers 3 and 4, where there is a dense concentration of nicotinic acetylcholine receptors (nAChRs) that has been hypothesized to regulate thalamocortical inputs. In support of the hypothesis, microinjection into layer 4 of the nonspecific nAChR antagonist mecamylamine (10 microM) strongly reduced sound-evoked responses. In contrast to the effects of acute nicotine and mecamylamine in adult control animals, neither drug was as effective in adult animals that had been treated with 5 days of chronic nicotine exposure (CNE) shortly after birth. Neonatal CNE also impaired performance on an auditory-cued active avoidance task, while having little effect on basic auditory or motor functions. Thus, neonatal CNE impairs nicotinic regulation of cortical function, and auditory learning, in the adult. Our results provide evidence that developmental nicotine exposure is responsible for auditory-cognitive deficits in the offspring of women who smoke during pregnancy, and suggest a potential underlying mechanism, namely diminished function of cortical nAChRs.
- Subjects :
- Animals
Animals, Newborn
Auditory Cortex drug effects
Auditory Cortex growth & development
Auditory Cortex physiopathology
Auditory Pathways drug effects
Auditory Pathways growth & development
Auditory Pathways physiopathology
Avoidance Learning drug effects
Avoidance Learning physiology
Cognition Disorders chemically induced
Cognition Disorders physiopathology
Disease Models, Animal
Female
Geniculate Bodies drug effects
Geniculate Bodies growth & development
Geniculate Bodies physiopathology
Language Development Disorders physiopathology
Learning Disabilities physiopathology
Male
Nicotinic Agonists adverse effects
Nicotinic Antagonists pharmacology
Pregnancy
Rats
Rats, Sprague-Dawley
Receptors, Nicotinic metabolism
Smoking adverse effects
Acetylcholine metabolism
Language Development Disorders chemically induced
Learning Disabilities chemically induced
Nicotine adverse effects
Prenatal Exposure Delayed Effects physiopathology
Receptors, Nicotinic drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0953-816X
- Volume :
- 24
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The European journal of neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 16848798
- Full Text :
- https://doi.org/10.1111/j.1460-9568.2006.04945.x