ABSTRACT
BACKGROUND AND OBJECTIVES: The basic principle of microdialysis is to mimic the function of a capillary blood vessel by perfusing physiologic liquid implanted into the target tissue. Amino acids are supposed to have functions for controlling the homeostasis of normal nasal mucosa and a role in the pathogenesis of allergic rhinitis. However, no studies have been conducted about the existence of amino acids in the nasal cavity. This study measures the concentration of 19 amino acids found in the nasal cavity of normal control and experimentally allergy-induced animal model in order to evaluate the difference in the concentration of amino acids between normal and allergic nasal mucosa. MATERIALS AND METHOD: An experimentally induced nasal allergy model was developed by intraperitoneal and intranasal sensitization with ovalbumin in Dunkin-Hartely guinea pigs according to a programmed protocol. A microdialysis probe was designed to be suitable to nasal mucosa using a Cuprophan hollow fiber (200 micrometer inner diameter, 300 micrometer outer diameter, 45 kDa molecular weight cut-off, Fitral, AN 69-HF). After verification of the probe, microdialysis was performed in the inferior turbinate submucosa of normal control (N=8) and experimental (N=8) groups. The concentration of 19 amino acids was analyzed using high performance liquid chromatography. Statistical analysis was performed using a student t-test. RESULTS: All 19 amino acids were validated at various concentrations in the nasal cavity. Glutamate (p=0.036) and GABA (p<0.001) concentrations were significantly higher in the experimental group than in the control group. CONCLUSION: The 19 amino acids measured existed in the nasal cavity at various concentrations, and the concentrations of glutamate and GABA were significantly higher in the allergy group than in the control group. The microdialysis technique is a powerful tool not only to measure endogenous substances for target organ chemistry but also to pharmacokinetically evaluate exogenous drug delivery processes in the nasal cavity.