Effect of nitric oxide synthase inhibitor on allergen- and hyperventilation-induced bronchoconstriction in guinea-pigs.
To elucidate the role of endogenous nitric oxide (NO) in allergen- (AIB) and hyperventilation-induced bronchoconstriction (HIB), the effects of an NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), on AIB and HIB were studied in guinea-pigs. In the AIB group, 21 anaesthetized guinea-pigs, actively sensitized with 1% ovalbumin, were challenged with aerosolized 0.1% ovalbumin solution under mechanical ventilation. In the HIB group, 14 guinea-pigs were challenged with hyperventilation (tidal volume of 12 mL x kg(-1) at 150 breaths x min(-1) with 21% O2 and 5% CO2 dry gas) for 5 min. In both groups, lung resistance (RL) was measured using a pressure-volume-sensitive body plethysmograph, with or without L-NAME pretreatment (8 mg x kg(-1) i.v. followed by 2 mg x kg(-1) x min(-1) i.v.). The NO precursor, L-arginine was injected at a rate of 15 mg x kg(-1) x min(-1) after L-NAME injection (10 mg x kg(-1)) in the AIB group. The results were as follows. In the AIB group, the maximal RL change was significantly potentiated by pretreatment with L-NAME. This potentiating effect of L-NAME was reversed by L-arginine. In the HIB group, the pretreatment with L-NAME had no effect on increases in RL. These findings suggest that endogenous nitric oxide may play an important role in the modulation of allergen-, but not hyperventilation-induced bronchoconstriction in guinea-pigs.
Nogami
H
H
Clinical Research Institute, National Minami Fukuoka Chest Hospital, Japan.
Umeno
E
E
Kano
S
S
Hirose
T
T
Nishima
S
S
D000403:Airway Resistance / Q000187:drug effects; D000485:Allergens; D000818:Animals; D001120:Arginine / Q000494:pharmacology; D016084:Bronchoconstriction / Q000187:drug effects* / Q000502:physiology; D006168:Guinea Pigs; D006985:Hyperventilation; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*
D000485:Allergens; D001120:Arginine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester