The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control

Persistent Link:
http://hdl.handle.net/10150/293608
Title:
The Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Control
Author:
Jaiswal, Stuti J.
Issue Date:
2013
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Developmental nicotine exposure (DNE) exerts negative consequences on the CNS via the activation of nAChRs that are available early and widely throughout development (refs). In this work, we examined how DNE changed excitatory and inhibitory neurotransmission in brainstem regions involved in central breathing control. Previous work using the brainstem-spinal cord preparation had shown that DNE augmented the respiratory-related response to AMPA, muscimol (a GABAA agonist), and glycine (Luo et al., 2004; Luo et al., 2007; Pilarski and Fregosi, 2009a). These studies used a split-bath preparation in which a drug (AMPA, muscimol, or glycine) was applied to medulla, and the frequency of the respiratory response (in the form of spontaneous, rhythmic bursting activity) was recorded from cervical nerve 4 (C4), which provides output to the diaphragm. Although these studies showed that DNE AMPA, GABA(A), and glycine neurotransmission in the medulla, the regions mediating the effect and the mechanism of DNE's action remained unclear. In this study we tested the hypothesis that the observed changes in respiratory burst frequency were mediated through the preBötzinger complex (preBötC), and the mechanism of enhanced activity involved an upregulation of neurotransmitter receptors. Additionally, we were interested in studying the effect of DNE on breathing-related motor pools, and therefore studied DNE's effect on excitatory and inhibitory neurotransmission in the XIIMN. We approached these questions and aims using a combination of techniques, including extracellular recordings from whole nerve output in rhythmic brainstem slices, immunohistochemistry, and Western blotting. We found enhanced AMPA, GABA(A), and glycine neurotransmission in the XIIMN and preBötC, and varying changes in neurotransmitter receptor expression in both groups. Additionally, we found a decrease in motoneuron soma size in XII motoneurons that stained positively for the glycine receptor. Overall, this study shows that DNE alters inhibitory and excitatory neurotransmission in both the preBötC and XIIMN, and that these changes may be mediated through a combination of change in cell size and receptor expression.
Type:
text; Electronic Dissertation
Keywords:
breathing; nicotine; Neuroscience; brainstem
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Neuroscience
Degree Grantor:
University of Arizona
Advisor:
Fregosi, Ralph F.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe Consequences of Developmental Nicotine Exposure on Neonatal Central Respiratory Controlen_US
dc.creatorJaiswal, Stuti J.en_US
dc.contributor.authorJaiswal, Stuti J.en_US
dc.date.issued2013-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractDevelopmental nicotine exposure (DNE) exerts negative consequences on the CNS via the activation of nAChRs that are available early and widely throughout development (refs). In this work, we examined how DNE changed excitatory and inhibitory neurotransmission in brainstem regions involved in central breathing control. Previous work using the brainstem-spinal cord preparation had shown that DNE augmented the respiratory-related response to AMPA, muscimol (a GABAA agonist), and glycine (Luo et al., 2004; Luo et al., 2007; Pilarski and Fregosi, 2009a). These studies used a split-bath preparation in which a drug (AMPA, muscimol, or glycine) was applied to medulla, and the frequency of the respiratory response (in the form of spontaneous, rhythmic bursting activity) was recorded from cervical nerve 4 (C4), which provides output to the diaphragm. Although these studies showed that DNE AMPA, GABA(A), and glycine neurotransmission in the medulla, the regions mediating the effect and the mechanism of DNE's action remained unclear. In this study we tested the hypothesis that the observed changes in respiratory burst frequency were mediated through the preBötzinger complex (preBötC), and the mechanism of enhanced activity involved an upregulation of neurotransmitter receptors. Additionally, we were interested in studying the effect of DNE on breathing-related motor pools, and therefore studied DNE's effect on excitatory and inhibitory neurotransmission in the XIIMN. We approached these questions and aims using a combination of techniques, including extracellular recordings from whole nerve output in rhythmic brainstem slices, immunohistochemistry, and Western blotting. We found enhanced AMPA, GABA(A), and glycine neurotransmission in the XIIMN and preBötC, and varying changes in neurotransmitter receptor expression in both groups. Additionally, we found a decrease in motoneuron soma size in XII motoneurons that stained positively for the glycine receptor. Overall, this study shows that DNE alters inhibitory and excitatory neurotransmission in both the preBötC and XIIMN, and that these changes may be mediated through a combination of change in cell size and receptor expression.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectbreathingen_US
dc.subjectnicotineen_US
dc.subjectNeuroscienceen_US
dc.subjectbrainstemen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineNeuroscienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorFregosi, Ralph F.en_US
dc.contributor.committeememberBailey, Elizabeth Fionaen_US
dc.contributor.committeememberFuglevand, Andrewen_US
dc.contributor.committeememberLevine, Richarden_US
dc.contributor.committeememberHenriksen, Eriken_US
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