Although the epiglottis plays a vital role in deglutition, histological studies of the epiglottis and surrounding ligaments associated with swallowing dysfunction are limited. Therefore, we performed histological observations to clarify age-related changes in the morphological characteristics of the epiglottis and surrounding structures. Tissue samples comprising the epiglottis and surrounding structures were collected from corpses that were both orally fed and tubefed during their lifetimes. Following hematoxylin and eosin, Elastica Van Gieson, and immunohistochemical staining procedures, the chondrocytes, connective tissue, and glandular tissue were observed under the epiglottis epithelium, and intervening adipose tissue was observed in the surrounding area. Fatty degeneration of acinar cells was also observed in the glandular tissue, possibly because of aging. Bundles of elastic fibers were present around the vascular wall in the periepiglottic ligament, but some were reduced. Furthermore, large amounts of collagen fibers ran toward and through the cartilage, whereas the mesh-like elastic fibers stopped in front of the cartilage. Microfibrils considered to be oxytalan fibers, which are thinner and shorter than elastic fibers, were observed around the vascular wall and in the fiber bundles. Agerelated changes included connective tissue fibrosis shown by the large amount of collagen fibers, atrophy of salivary glands, and an accompanying increase in adipose tissue. Regarding stretchability and elasticity, the elastic fibers may have an auxiliary function for laryngeal elevation during deglutition. This suggests that disuse atrophy of the laryngeal organs with or without oral intake might reduce the amount of elastic fiber in older adults.

Background: In recent years, dexmedetomidine (DEX) has been proposed as a useful vasoconstrictor for local anesthesia because it is less effective in circulation than clonidine of antihypertensive drugs. In addition, DEX is expected to act as a vasoconstrictor during local anesthesia. However, histomorphometric studies demonstrating that DEX exerts vasoconstrictive effects are lacking. This study aimed to clarify whether DEX exerts a histomorphologically vasoconstrictive effect on blood vessels in the mandible of rats. Methods: A total of 12 male Wistar rats were used. General anesthesia was induced and maintained using sevoflurane. Normal saline (0.2 ml) was injected on the left side of the jaw (DEX (-) effect site) and 0.2 ml normal saline containing 12.5 µg/ml DEX was injected on the right side of the jaw (DEX (+) effect site).The puncture point was located on the mesial side of the first molar, 1 mm away from the gingival sulcus.Following decalcification, the specimens were paraffinized and sagittally sliced into 20 μm-thick sections, followed by staining with anti-α smooth muscle actin antibody. The intravascular lumen area was measured in the oral mucosa, periodontal ligament, mandibular bone above the root apex, mandibular bone below the root apex, and dental pulp. The unpaired t-test was used for statistical analysis, and a P value < 0.05 was considered statistically significant. Results: Compared to the DEX (-) effect site, the intravascular lumen area in the oral mucosa and periodontal ligament of the DEX (+) effect site was significantly decreased. No significant difference was observed in the intravascular lumen area between the DEX (-) and DEX (-) effect sites in the mandibular bone above and below the root apex and dental pulp. Conclusion A direct vasoconstrictive effect of DEX was not observed in the intravascular lumen of the mandibular bone above and below the root apex and dental pulp; however, it was observed in the oral mucosa and periodontal ligament.

Background: In recent years, dexmedetomidine (DEX) has been proposed as a useful vasoconstrictor for local anesthesia because it is less effective in circulation than clonidine of antihypertensive drugs. In addition, DEX is expected to act as a vasoconstrictor during local anesthesia. However, histomorphometric studies demonstrating that DEX exerts vasoconstrictive effects are lacking. This study aimed to clarify whether DEX exerts a histomorphologically vasoconstrictive effect on blood vessels in the mandible of rats. Methods: A total of 12 male Wistar rats were used. General anesthesia was induced and maintained using sevoflurane. Normal saline (0.2 ml) was injected on the left side of the jaw (DEX (-) effect site) and 0.2 ml normal saline containing 12.5 µg/ml DEX was injected on the right side of the jaw (DEX (+) effect site).The puncture point was located on the mesial side of the first molar, 1 mm away from the gingival sulcus.Following decalcification, the specimens were paraffinized and sagittally sliced into 20 μm-thick sections, followed by staining with anti-α smooth muscle actin antibody. The intravascular lumen area was measured in the oral mucosa, periodontal ligament, mandibular bone above the root apex, mandibular bone below the root apex, and dental pulp. The unpaired t-test was used for statistical analysis, and a P value < 0.05 was considered statistically significant. Results: Compared to the DEX (-) effect site, the intravascular lumen area in the oral mucosa and periodontal ligament of the DEX (+) effect site was significantly decreased. No significant difference was observed in the intravascular lumen area between the DEX (-) and DEX (-) effect sites in the mandibular bone above and below the root apex and dental pulp. Conclusion A direct vasoconstrictive effect of DEX was not observed in the intravascular lumen of the mandibular bone above and below the root apex and dental pulp; however, it was observed in the oral mucosa and periodontal ligament.

Background: In recent years, dexmedetomidine (DEX) has been proposed as a useful vasoconstrictor for local anesthesia because it is less effective in circulation than clonidine of antihypertensive drugs. In addition, DEX is expected to act as a vasoconstrictor during local anesthesia. However, histomorphometric studies demonstrating that DEX exerts vasoconstrictive effects are lacking. This study aimed to clarify whether DEX exerts a histomorphologically vasoconstrictive effect on blood vessels in the mandible of rats. Methods: A total of 12 male Wistar rats were used. General anesthesia was induced and maintained using sevoflurane. Normal saline (0.2 ml) was injected on the left side of the jaw (DEX (-) effect site) and 0.2 ml normal saline containing 12.5 µg/ml DEX was injected on the right side of the jaw (DEX (+) effect site).The puncture point was located on the mesial side of the first molar, 1 mm away from the gingival sulcus.Following decalcification, the specimens were paraffinized and sagittally sliced into 20 μm-thick sections, followed by staining with anti-α smooth muscle actin antibody. The intravascular lumen area was measured in the oral mucosa, periodontal ligament, mandibular bone above the root apex, mandibular bone below the root apex, and dental pulp. The unpaired t-test was used for statistical analysis, and a P value < 0.05 was considered statistically significant. Results: Compared to the DEX (-) effect site, the intravascular lumen area in the oral mucosa and periodontal ligament of the DEX (+) effect site was significantly decreased. No significant difference was observed in the intravascular lumen area between the DEX (-) and DEX (-) effect sites in the mandibular bone above and below the root apex and dental pulp. Conclusion A direct vasoconstrictive effect of DEX was not observed in the intravascular lumen of the mandibular bone above and below the root apex and dental pulp; however, it was observed in the oral mucosa and periodontal ligament.