Anti-cholinergic effect of singulair on isolated rat's tracheal smooth muscle.
Singulair (Montelukast) is a potent and selective leukotriene D(4) receptor antagonist, often used in treating inflammatory conditions of the respiratory system such as allergic rhinitis and asthma. However, the effects of singulair given intratracheally have rarely been well explored. To verify the effect of singulair, which acts on the tracheal smooth muscle directly in vitro. We used our preparation to test the effects of singulair on isolated rat's tracheal smooth muscle. The following assessments of singulair were performed: (1) effect on the tracheal smooth muscle resting tension, (2) effect on contraction caused by 10(-6) M methacholine as a parasympathetic mimetic, and (3) effect of the drugs on electrically induced tracheal smooth muscle contractions. The results indicated that the addition of methacholine to the incubation medium caused the trachea to contract in a dose-dependent manner. Addition of singulair at doses of 10(-5) M or above elicited a significant relaxation response to 10(-6) M methacholine-induced contraction. Singulair could not inhibit electrical field stimulation-induced spike contraction. It also had a minimal effect on the basal tension of trachea as the concentration increased. This study showed that the high concentrations of singulair also had an anti-cholinergic effect for relieving symptoms of asthma.
Department of Otolaryngology-Head and Neck Surgery, Tri-Service General Hospital, National Defense Medical Center, No. 325, Sec. 2, Cheng-Gong Road, Neihu District, Taipei, Taiwan.
Li-Hsiang
LH
Cheng
Chuan-Hsiang
CH
Kao
Chih-Hung
CH
Wang
Yueng-Hsiang
YH
Chu
Jia-Yi
JY
Wang
Hsing-Won
HW
Wang
D000085:Acetates / Q000494:pharmacology*; D000818:Animals; D018927:Anti-Asthmatic Agents / Q000494:pharmacology*; D001249:Asthma / Q000188:drug therapy; D016085:Bronchoconstrictor Agents / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D003521:Cyclopropanes; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D066298:In Vitro Techniques; D016210:Methacholine Chloride / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009129:Muscle Tonus / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011804:Quinolines / Q000494:pharmacology*; D051381:Rats; D013440:Sulfides; D014132:Trachea / Q000187:drug effects*
D000085:Acetates; D018927:Anti-Asthmatic Agents; D016085:Bronchoconstrictor Agents; D018680:Cholinergic Antagonists; D003521:Cyclopropanes; D011804:Quinolines; D013440:Sulfides; D016210:Methacholine Chloride; C093875:montelukast