[Mechanisms of the effect of oxidants on the respiratory system].
BACKGROUND
It is known that oxidants may evoke changes of respiratory tract functions. The precise mechanisms of these changes are yet unknown.


OBJECTIVE
In this study possible participation of eicosanoids, cytochrome P-450 and reactive oxygen species in the changes of airways reactivity evoked by toluene exposure as the source of free radicals was followed up by an indirect method.


METHODS
Used drugs--naproxen (50 mg/kg b.w.), cimetidine (50 mg/kg b.w.) and N-acetylcysteine (300 mg/kg b.w.) were administered in two doses (first 30 minutes before exposure to toluene, second six hours after first dose). After exposure to toluene (2 hours in each of 3 consecutive days) was followed up reactivity of tracheal and lung smooth muscle to histamine in "in vitro" conditions. The studied substances were not administered in the control group of animals.


RESULTS
In pretreated animals exposed to toluene the administration of naproxen, cimetidine and N-acetylcysteine does not provoke pronounced changes of tracheal smooth muscle reactivity compared to control group. More pronounced effect of these drugs with decrease contraction amplitude was detected on lung smooth muscle reactivity.


CONCLUSIONS
According to our results it is not possible to determine the precise mechanisms which participate in changes of airways reactivity. There are probably multifactorial in nature.
Strapkova
A
A
Institute of Pharmacology, Jessenius Medical Faculty, Comenius University, Martin, Slovakia.
Nosalova
G
G
Franova
S
S
Adamicova
K
K
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D002927:Cimetidine / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D065607:Cytochrome P-450 Enzyme Inhibitors; D016166:Free Radical Scavengers / Q000494:pharmacology; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects* / Q000473:pathology / Q000502:physiology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D009288:Naproxen / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology*; D014050:Toluene / Q000494:pharmacology*; D014132:Trachea / Q000187:drug effects* / Q000473:pathology / Q000502:physiology
D016861:Cyclooxygenase Inhibitors; D065607:Cytochrome P-450 Enzyme Inhibitors; D016166:Free Radical Scavengers; D016877:Oxidants; D014050:Toluene; D009288:Naproxen; D002927:Cimetidine; D000111:Acetylcysteine