Effects of bakumondoto on neuropeptide levels in human saliva and plasma

麦門冬湯は,唾液腺機能異常に関連するドライマウスなどの口腔内乾燥症状に対して経験的に使用される。唾液腺にはsubstance P,calcitonin gene-related peptide(CGRP),and vasoactive intestinal polypeptide(VIP)などの神経ペプチドが局在している。我々は,健常人の唾液及び血漿中のsubstance P,calcitonin gene-related peptide(CGRP),and vasoactive intestinal polypeptide(VIP)濃度に与える麦門冬湯の効果を検討した。麦門冬湯(18.0g)あるいは対照薬を5人の健常人へ経口投与し,唾液ならびに血液を,投与前及び投与後20〜240分に採取し,高感度酵素免疫測定法により各種神経ペプチド濃度を測定した。その結果,本剤投与後のsubstance P,CGRPの唾液中濃度は,対照群に比較して有意に上昇した。また本剤投与後の唾液分泌量は増大傾向であった。以上の結果から,麦門冬湯は唾液腺におけるsubstance PとCGRPに作用し,これらの効果が唾液分泌を刺激している可能性が示された。また,唾液と血漿中神経ペプチド濃度をモニターすることは,麦門冬湯の効果を予測することが可能であると考えられた。

Bakumondoto is empirically used to treat to dry mouth (xerostomia) associated with salivary gland dysfunction. Salivary glands are supplied with nerve fibers that contain neruopeptides, such as substance P, calcitonin gene-related peptide (CGRP), and vasoactive intestinal polypeptide (VIP). These neuropeptides are important modulators of salivation. We studied the effect of bakumondoto on substance P-, CGRP-, VIP-like immunoreactive substances (IS) in saliva and plasma taken from healthy subjects. Bakumondoto (18.0g) or placebo was orally administered to five healthy males. Saliva and blood samples were taken before, and at 20-240min after administration, followed by the extracting procedure, and submitted to a highly sensitive enzyme immunoassay system for neuropeptides. A single oral administration of bakumondoto caused significant increases in saliva substance P-and CGRP-IS levels compared with placebo. And this medicine tended to raise saliva volume. In this study, we concluded bakumondoto might affect substance P and CGRP locally in the salivary gland and the elevated levels of these neuropeptides might stimulate production of saliva. Also, the monitoring of saliva and plasma neuropeptide levels might be able to predict the pharmacologic effects of bakumondoto.