Functional Development of Nociceptors in the Oral Mucosa

用自行研制的颌神经体外制剂对口腔黏膜伤害性感受器的功能发育进行了研究。健康雄性Wistar大鼠36只，体质量250~350g。这些动物被关在传统的丙烯酸笼子里，笼子里有柔软的床上用品，光照周期为14小时，黑暗周期为10小时。每只动物只有一次记录，实验结束后立即处死动物，心内注射硫代戊酸钠(100 mg/kg，Isozol^[0！R]，Yoshitomi Pharmacy，日本大阪)。所有实验均得到长崎大学动物福利委员会的批准。在口腔粘膜中，发现了四种伤害性感受器亚型：A-Delta高阈值机械伤害性感受器、A-Delta多模式伤害性感受器、C高阈值机械伤害性感受器、C多模式伤害性感受器。这些伤害性感受器在出生后3-5周成熟。在发育过程中，由A-Delta或C传入纤维支配的多模式伤害性感受器比例下降。

Functional Development of the oral mucosal nociceptors was investigated using in vitro Jawnerve preparation which was recently developed by ours. A total of 36 male Wistar albino rats weighing 250-350 g were tested. The animals were housed in conventional acrylic cages with soft bedding under a 14 h light/10 h dark cycle. Only one recording was obtained from each animal and the animal was sacrificed immediately after experiment with an intracardiac injection of thiamylal sodium (100 mg/kg, Isozol^【○!R】, Yoshitomi Pharmacy, Osaka, Japan). All experiments were approved by the Animal Care Welfare Committee Nagasaki University.In the oral mucosa, four subtypes of nociceptors were found: A-delta high threshold mechanonociceptor, A-delta polymodal nociceptor, C high threshold mechanonociceptor, C polymodal nocieptor. These nociceptors were maturated by 3-5 weeks after birth. The ratio of polymodal nociceptors innervated by A-delta or C afferent fiber was decreased during development.