Effect of inhaled histamine on airway epithelial cell swelling in ozone-exposed Guinea pigs.
BACKGROUND
It has been reported that histamine stimulates ion channels on airway epithelial cells and induces changes in osmolarity and the ion composition of the periciliary field of airway epithelia.


OBJECTIVE
To investigate the effect of inhaled histamine on epithelial cell swelling, we studied the role of airway epithelial cells under histamine inhalation challenge in an animal model of airway inflammation using ozone exposure.


METHODS
After exposure to 3.0 ppm ozone for 2 h, guinea pigs were anesthetized and tracheostomized, and then, lung resistance (R(L)) was measured. Histamine inhalation challenge and histological examination were performed.


RESULTS
The values of R(L) before histamine inhalation in the control group and the ozone-exposed group were 0.26 +/- 0.11 and 0.45 +/- 0.34 cm H(2)O/s, respectively. R(L) increased significantly after histamine inhalation both in the control and the ozone-exposed groups. The threshold of histamine (PC(200)) in the ozone-exposed group was significantly lower than that in the control group. A significant swelling of the epithelial cells after histamine inhalation was observed both in the control and the ozone-exposed groups, with a greater increase in the ozone-exposed group compared with the control group. However, no change in wall thickness was observed in the histamine/antihistamine or the ozone/histamine/antihistamine group.


CONCLUSIONS
Our results suggest the possibility that the airway epithelial cell swelling plays a role in the increase in R(L) after histamine inhalation, especially in the presence of airway inflammation.
Muramatsu
Reiko
R
Department of Pediatrics and Developmental Medicine, Graduate School of Medicine, Gunma University, Gunma, Japan.
Mochizuki
Hiroyuki
H
Arakawa
Hirokazu
H
Tokuyama
Kenichi
K
Morikawa
Akihiro
A
D000403:Airway Resistance / Q000187:drug effects / Q000502:physiology; D000818:Animals; D016535:Bronchial Hyperreactivity / Q000139:chemically induced / Q000188:drug therapy; D004847:Epithelial Cells / Q000187:drug effects*; D006168:Guinea Pigs; D006632:Histamine / Q000008:administration & dosage*; D018494:Histamine Agents / Q000008:administration & dosage*; D007473:Ion Channels / Q000187:drug effects; D008297:Male; D010083:Oxidants, Photochemical / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D020545:Respiratory Mucosa / Q000187:drug effects*
D018494:Histamine Agents; D007473:Ion Channels; D010083:Oxidants, Photochemical; D010126:Ozone; D006632:Histamine