Study on the Rat Esophageal Microcirculation that Mediated Inflammatory Response Evoked by Capsaicin and Substance P

• Main Authors: Yu-Chung Chen, 陳豫中
• Other Authors: Hung-Tu Huang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/22969618106691837078

碩士 === 國立中山大學 === 生物科學系研究所 === 90 === 【Abstract】 Neurogenic inflammation is an acute inflammatory tissue response, that is mediated by sensory axon reflex. Accompanied with neurogenic inflammation, plasma extravasation, occurs in the eyes, esophagus, bladder, joints, the tip of tongue, and the respiratory tract of the mammal. Recently, many studies have investigated the neurogenic inflammation by electrical stimulation of nerves and intravascular injection of irritants. Upon stimulation, the sensory nerve endings in mucosa can release neuropeptides such as substance P, that causes formation of the venular endothelial gaps, plasma extravasation and tissue edema in various organs. Substance P also cause smooth muscle contraction and mucus secretion in the respiratory tract. Neurogenic plasma extravasation has been studied extensively in the trachea, and bronchi, but rarely in the esophagus. It is known that a plexus of substance P-immunoreactive axons exists in the mucosal and submucosal layers. They play an important role in releasing substance P to act on the receptors of the venular endothelium through diffusion. Based on plasma extravasation and other studies related to the respiratory tract, the purpose of the present study was to investigate neurogenic inflammatory response in the esophagus of the digestive tract. In this study, capsaicin (90 µg/ml/kg) and substance P (3 µg/ml/kg) were used as the irritant and inflammatory mediator, respectively to reduce neurogenic inflammation in the esophagus. India ink was used to label the affected venules. The magnitude of the neurogenic inflammation was expressed as area density of India ink-labeled leaky venules. Histopathological changes in the esophageal tissue were studied under the light microscope. The result of this study indicated that capsaicin at the dose of (90 µg/ml/kg) and substance P at the dose of (3 µg/ml/kg) caused similar magnitude of inflammation in the esophagus. India ink-labeled venules distributed like a network in the mucosal tissue and in connective tissue of the submucosal layer. The upper, middle and lower parts of esophagus exhibited the same degree of inflammatory response, that was similar to that in the lower respiratory tract as the previous studies reported. These results suggest that nerve branches from the vagal trunk send sensory axons to innervate both the esophagus and airways.