Journal article
Degeneration of vagal efferent axons and terminals in cardiac ganglia of aged rats
Journal of comparative neurology (1911), Vol.504(1), pp.74-88
09/01/2007
DOI: 10.1002/cne.21431
PMID: 17614301
Abstract
Baroreflex control of the heart rate is significantly reduced during aging. However, neural mechanisms that underlie such a functional reduction are not fully understood. We injected the tracer DiI into the left nucleus ambiguus (NA), then used confocal microscopy and a Neurolucida Digitization System to examine qualitatively and quantitatively vagal efferent projections to cardiac ganglia of young adult (5-6 months) and aged (24-25 months) rats (Sprague Dawley). Fluoro-Gold was injected intraperitoneally to counterstain cardiac ganglionic principal neurons (PNs). In aged, as in young rats, NA axons projected to all cardiac ganglia and formed numerous basket endings around PNs in the hearts. However, significant structural changes were found in aged rats compared with young rats. Vagal efferent axons contained abnormally swollen axonal segments and exhibited reduced or even absent synaptic-like terminals around PNs, such that the numbers of vagal fibers and basket endings around PNs were substantially reduced (P < 0.01). Furthermore, synaptic-like varicose contacts of vagal cardiac axons with PNs were significantly reduced by approximately 50% (P < 0.01). These findings suggest that vagal efferents continue to maintain homeostatic control over the heart during aging. However, the marked morphological reorganization of vagal efferent axons and terminals in cardiac ganglia may represent the structural substrate for reduced vagal control of the heart rate and attenuated baroreflex function during aging.
Details
- Title: Subtitle
- Degeneration of vagal efferent axons and terminals in cardiac ganglia of aged rats
- Creators
- Jing Ai - Biomolecular Science Center, Burnett College of Biomedical Sciences, University of Central Florida, Orlando, Florida 32816, USADavid GozalLihua LiWilliam B WeadMark W ChapleauRobert WursterBaofeng YangHulun LiRugao LiuZixi Cheng
- Resource Type
- Journal article
- Publication Details
- Journal of comparative neurology (1911), Vol.504(1), pp.74-88
- Publisher
- United States
- DOI
- 10.1002/cne.21431
- PMID
- 17614301
- ISSN
- 0021-9967
- eISSN
- 1096-9861
- Grant note
- AG-021020 / NIA NIH HHS S10RR-019391 / NCRR NIH HHS HL-796369 / NHLBI NIH HHS HL-75034 / NHLBI NIH HHS AG-023297 / NIA NIH HHS
- Language
- English
- Date published
- 09/01/2007
- Academic Unit
- Molecular Physiology and Biophysics; Internal Medicine
- Record Identifier
- 9984025322202771
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