Journal article
Structural remodeling of nucleus ambiguus projections to cardiac ganglia following chronic intermittent hypoxia in C57BL/6J mice
Journal of comparative neurology (1911), Vol.509(1), pp.103-117
07/01/2008
DOI: 10.1002/cne.21732
PMID: 18425809
Abstract
The baroreflex control of heart rate (HR) is reduced following chronic intermittent hypoxia (CIH). Since the nucleus ambiguus (NA) plays a key role in baroreflex control of HR, we examined whether CIH remodels vagal efferent projections to cardiac ganglia. C57BL/6J mice (3-4 months of age) were exposed to either room air (RA) or CIH for 3 months. Confocal microscopy was used to examine NA axons and terminals in cardiac ganglia following Fluoro-Gold (FG) injections to label cardiac ganglia, and microinjections of tracer DiI into the left NA to anterogradely label vagal efferents. We found that: 1) Cardiac ganglia were widely distributed on the dorsal surface of the atria. Although the total number of cardiac ganglia did not differ between RA and CIH mice, the size of ganglia and the somatic area of cardiac principal neurons (PNs) were significantly decreased (P < 0.01), and the size of the PN nuclei was increased following CIH (P < 0.01). 2) NA axons entered cardiac ganglia and innervated PNs with dense basket endings in both RA and CIH mice, and the percentage of innervated PNs was similar (RA: 50 +/- 1.0%; CIH: 49 +/- 1.0%; P > 0.10). In CIH mice, however, swollen cardiac axons and terminals without close contacts to PNs were found. Furthermore, varicose endings around PNs appeared swollen and the axonal varicose area around PNs was almost doubled in size (CIH: 163.1 +/- 6.4 microm(2); RA: 88 +/- 3.9 microm(2), P < 0.01). Thus, CIH significantly altered the structure of cardiac ganglia and resulted in reorganized vagal efferent projections to cardiac ganglia. Such remodeling of cardiac ganglia and vagal efferent projections provides new insight into the effects of CIH on the brain-heart circuitry of C57BL/6J mice.
Details
- Title: Subtitle
- Structural remodeling of nucleus ambiguus projections to cardiac ganglia following chronic intermittent hypoxia in C57BL/6J mice
- Creators
- Min Lin - Biomolecular Science Center, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32816, USAJing AiLihua LiChenghui HuangMark W ChapleauRugao LiuDavid GozalWilliam B WeadRobert D WursterZixi ' Jack ' Cheng
- Resource Type
- Journal article
- Publication Details
- Journal of comparative neurology (1911), Vol.509(1), pp.103-117
- Publisher
- United States
- DOI
- 10.1002/cne.21732
- PMID
- 18425809
- ISSN
- 0021-9967
- eISSN
- 1096-9861
- Grant note
- P01 HL014388 / NHLBI NIH HHS AG-021020 / NIA NIH HHS RR-019391 / NCRR NIH HHS HL-75034 / NHLBI NIH HHS HL-79636 / NHLBI NIH HHS
- Language
- English
- Date published
- 07/01/2008
- Academic Unit
- Molecular Physiology and Biophysics; Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine
- Record Identifier
- 9984025325902771
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