title: [Effects of repeated esophageal acid infusion on airway resistance and airway reactivity in guinea pigs and the mechanism].
abstract: OBJECTIVE
  To observe the effect of repeated esophageal acid infusion on specific airway resistance (sRaw) and airway reactivity in the guinea pigs and explore the mechanism.
  
  
  METHODS
  sRaw and airway reactivity were measured by double-chamber plethysmography in normal control group (group N), saline control group (group NS), and repeated acid irrigation group (group H). The initial measurement was used as the baseline sRaw and airway reactivity (1d1), and 2 h after the initial measurement, sRaw and airway reactivity were measured again (1d2). Similarly, such measurements were repeated on the 15th day for all the guinea pigs (15d1, 15d2) with a 2-h interval. The content of Substance P (SP) and vasoactive intestinal peptide (VIP) in lung tissue, trachea, BALF and ganglion were detected by ELISA.
  
  
  RESULTS
  The percent change of sRaw, (15d2-1d1)/1d1 in group H was significantly higher than that in group N. The differences in the airway reactivity of the group N, group NS, and group H were not statistically significant. The SP content in the lung, trachea, ganglion and bronchoalveolar lavage fluid (BALF) in group H was significantly higher than those in group N. The SP content in ganglion showed a significant positive correlation to that in the trachea. No significant differences were found in the VIP content in the lung, trachea, ganglion or BALF between the groups.
  
  
  CONCLUSIONS
  Repeated esophageal acid infusion increases the airway resistance, but not the airway reactivity in normal guinea pigs. SP may be involved in development of high sRaw through the esophageal-tracheobronchial reflex.
authors.affiliation: State Key Laboratory of Respiratory Disease, Guangzhou Medical College/ First Affiliated Hospital of Guangzhou Medical College, Guangzhou 510120, China. yao7722 @yahoo.com.cn
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Yao
authors.forename: Ke-Fang
authors.initials: KF
authors.lastname: Lai
authors.forename: Yuan-Ming
authors.initials: YM
authors.lastname: Luo
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Liu
authors.forename: Ru-Chong
authors.initials: RC
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Luo
authors.forename: Nan-Shan
authors.initials: NS
authors.lastname: Zhong
mesh_terms: D000403:Airway Resistance; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D004947:Esophagus; D005764:Gastroesophageal Reflux / Q000378:metabolism* / Q000503:physiopathology; D006168:Guinea Pigs; D008168:Lung / Q000378:metabolism; D008297:Male; D012137:Respiratory System; D013373:Substance P / Q000378:metabolism*; D014132:Trachea / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
chemical_list: D013373:Substance P; D014660:Vasoactive Intestinal Peptide