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CARDIAC NEUROPATHY IN TYPE 1 DIABETIC MICE (OVE 26)
Author(s) -
AI Jing,
LIU B.,
Gozal D.,
Epstein P.,
Cheng Z.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a299
Subject(s) - efferent , medicine , endocrinology , chemistry , afferent
Baroreflex control of heart rate is reduced in type 1 diabetes. However, the neural mechanism for such a reduction is poorly understood. In this study, we hypothesized that vagal efferent projections to cardiac ganglia in OVE26 mice were significantly reduced. DiI was microinjected into NA to anterogradely label vagal efferent axons and terminals in control (FVB) and OVE26 mice (n=6/group) at 5 months old. Fluoro‐Gold (FG) was injected (i.p.) to label cardiac ganglia. Confocal microscopy and Neurolucida tracing system were used to examine cardiac ganglia and vagal innervation of cardiac ganglia in the whole‐mount atria. Our data indicated that (1) DiI labeled vagal axons entered cardiac ganglia and formed extensive basket terminal synapses around individual cardiac neurons in both mice. However, the density of basket endings (OVE 26: 30.8 ¡À1.9% vs. FVB: 54.3¡À3.1%) and the number of the vagal axon synaptic contacts around cardiac neurons (OVE 26: 28.1¡À1.5 vs. FVB: 67.9¡À3.8, P<0.001; n=300) were all significantly decreased in OVE26 mice. (2) The size of cardiac ganglia in OVE 26 mice was significantly reduced (FVB: 0.16¡À0.02mm2 and OVE26: 0.11¡À0.01mm2, p<0.05; n=20), even though the total numbers of cardiac ganglia did not significantly differ (FVB: 18.3¡À0.9 and OVE26: 16.8¡À1.0, p>0.05; n=20). Further, the somata area of cardiac neurons was significantly reduced in OVE26 mice (OVE 26: 280.8 ¡À 5.1 ¦Ìm2 vs FVB: 434.9¡À8.1¦Ìm2; p<0.001; n=300), but the total number of cardiac neurons was not different between two groups (P>0.05). We have demonstrated that chronic type 1 diabetes induced a significant morphological change of cardiac ganglia and reduced vagal efferent innervation of the heart. Supported by NIH HL079636.