Aortic Depressor Nerve Myelinated Fibers in Acute and Chronic Experimental Diabetes

Preliminary data from our laboratory have demonstrated baroreflex dysfunction as early as 5 days after the onset of experimental diabetes in rats. The aim of the present study was to determine the morphologic alterations of the aortic depressor nerve of rats submitted to acute (15 days) or chronic (...

Full description

Saved in:
Bibliographic Details
Published in:American journal of hypertension 2006-02, Vol.19 (2), p.153-160
Main Authors: Fazan, Valéria Paula Sassoli, Salgado, Helio Cesar, Barreira, Amilton Antunes
Format: Article
Language:English
Subjects:
Acute Disease
Animals
Aorta - innervation
Aorta - pathology
Aortic depressor nerve
Arterial hypertension. Arterial hypotension
Associated diseases and complications
Atrophy
Axons - pathology
Baroreflex - physiology
Biological and medical sciences
Blood and lymphatic vessels
Cardiology. Vascular system
Chronic Disease
Diabetes Mellitus, Experimental - chemically induced
Diabetes Mellitus, Experimental - physiopathology
Diabetes. Impaired glucose tolerance
Disease Models, Animal
Disorders of blood lipids. Hyperlipoproteinemia
Endocrine pancreas. Apud cells (diseases)
Endocrinopathies
experimental diabetes
Male
Medical sciences
Metabolic diseases
morphology
morphometry
Nerve Fibers, Myelinated - physiology
Nerve Fibers, Myelinated - ultrastructure
rat
Rats
Rats, Wistar
Severity of Illness Index
Streptozocin - toxicity
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Preliminary data from our laboratory have demonstrated baroreflex dysfunction as early as 5 days after the onset of experimental diabetes in rats. The aim of the present study was to determine the morphologic alterations of the aortic depressor nerve of rats submitted to acute (15 days) or chronic (12 weeks) experimental diabetes. Wistar rats received a single intravenous injection of streptozotocin (50 mg/kg) 15 days or 12 weeks before the experiments. Time control animals received vehicle. Under pentobarbital anesthesia the aortic depressor nerves were identified by means of electroneurographic recording simultaneously with the recording of arterial pressure. After identification, the aortic depressor nerves were prepared for light microscopy and our analysis only included the myelinated fibers. Five of 10 aortic depressor nerves from animals with acute diabetes showed clear signs of axonal atrophy with significantly smaller average diameter of myelinated fibers (1.9 ± 0.1 μm) and their axons (1.0 ± 0.1 μm) than the time control (2.1 ± 0.1 μm and 1.2 ± 0.1 μm, respectively). Histograms of the G-ratio (ratio between axon diameter and total fiber diameter—an index of axonal atrophy) distribution of acute diabetic animal nerves were shifted to the left. All aortic depressor nerves from animals with chronic diabetes showed signs of axonal atrophy with the average diameter of myelinated fibers (2.3 ± 0.1 μm) and their axons (1.2 ± 0.1 μm) also being significantly smaller than the time control (2.6 ± 0.2 μm and 1.5 ± 0.1 μm, respectively). These findings provide morphologic support for an impaired baroreflex during acute and chronic experimental diabetes.
ISSN:0895-7061
1879-1905
1941-7225
DOI:10.1016/j.amjhyper.2005.07.023