Inhibitory effect of flumequine, enoxacin and norfloxacin on the GABA-induced contractile effect on the guinea pig ileum.
1. In the present study the effect of flumequine, enoxacin and norfloxacin on the GABA-elicited contractions (EC50 1.10 x 10(-5) M) on the isolated guinea pig ileum was investigated, in a comparative manner. 2. All three fluoroquinolones dose-dependently antagonised the GABA-induced contractions in a non-competitive manner, but no statistical difference in the degree of the antagonism they produced was noted. Besides, they did not influence the ileal cholinergic contractions induced by exogenous acetylcholine. 3. These results suggest that the above fluoroquinolones tested dose-dependently inhibit the contractile effect of GABA on the guinea pig ileum and this inhibition seems to be associated with an antagonistic action of the fluoroquinolones at GABAA-receptors present in the guinea pig ileum.
Koutsoviti-Papadopoulou
M
M
Department of Pharmacology, Faculty of Veterinary Medicine, Aristotelian University, Thessaloniki, Greece.
Kounenis
G
G
Elezoglou
V
V
D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D015365:Enoxacin / Q000494:pharmacology*; D005260:Female; D024841:Fluoroquinolones; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects*; D008297:Male; D009119:Muscle Contraction; D009643:Norfloxacin / Q000494:pharmacology*; D011807:Quinolizines / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D000890:Anti-Infective Agents; D024841:Fluoroquinolones; D011807:Quinolizines; D015365:Enoxacin; D005680:gamma-Aminobutyric Acid; D009643:Norfloxacin; C012976:flumequine