Relationship between esophageal morphology in rabbits and autonomic regulation type

The morphofunctional characteristics of the organism as a whole and of individual organs in particular depend on regulatory influences of the autonomic nervous system. The balance between sympathetic and parasympathetic divisions determines a sp e cific autonomic regulation type. The influence of this factor on esophageal anatomy was investigated in male Blanc de Termonde rabbits. Each animal underwent electrocardiographic examination to determine autonomic tone. After euthanasia, histological sections were prepared from the thoracic esophagus, and the areas of the esophageal wall layers and their components were measured. Rabbits with high sympathetic tone showed increased areas of the mucosa (epithelium, keratinized layer, and lamina propria) and the submucosa. The epithelial area in the rabbits with high sympathetic tone (1.925 ± 0.050 mm²) exceeded that in the rabbits with high parasympathetic tone by 0.221 mm² (P = 0.0076). The r abbits with high parasympathetic tone had larger areas of the outer longitudinal, circular, and inner longitudinal layers of the muscular layer . The total area of muscular membrane in the rabbits with high parasympathetic tone (9.977 ± 0. 281 mm²) exceeded that in the rabbits with balanced autonomic tone by 1.465 mm² (P = 0.0430). For all types of autonomous regulation, the muscular membrane showed numerous correlations with other structural components of the esophageal wall. The r abbits with balanced autonomic tone were characterized by the largest areas of the serosa and the muscularis mucosae. The muscularis mucosae area was lowest in the rabbits with high parasympathe t ic tone (0.661 ± 0.018 mm²), which was 0.089 mm² smaller than in the rabbits with balanced autonomic tone (P = 0.0151). Aut o nomic regulation type was also reflected in the proportions of esophageal wall components (mucosa, submucosa, muscular membrane, serosa). The ratio was 20.98% – 12.64% – 62.06% – 4.32% in the rabbits with high sympathetic tone, 21.73% – 10.22% – 61.10% – 6.95% in the rabbits with balanced autonomic tone, and 19.08% – 10.18% – 67.34% – 3.40%. in the rabbits with high parasympathetic tone. High parasympathetic tone was associated with the lowest variability of most parameters, and similar variability was observed in the rabbits with high sympathetic tone. By contrast, the rabbits with balanced autonomic tone showed a marked increase in the coefficient of variation.