Effect of levocetirizine on the contraction induced by histamine on isolated rabbit bronchioles from precision-cut lung slices.
The present experiments were designed to study the effects of levocetirizine (a potent selective histamine H(1) antagonist) on the contraction induced by histamine on isolated rabbit bronchioles using the precision-cut lung slice technology. Histamine induced a concentration-dependent contraction of isolated rabbit bronchioles (pD(2) value of 5.6). Mepyramine (0.01-1 micromol/l) induced a shift to the right without any decrease in the concentration-response curve to histamine (pA(2) value of 8.2). Levocetirizine (0.03-0.1 micromol/l) induced both a shift to the right and a decrease in the maximal amplitude of the concentration-response curve to histamine (pA(2) and pD'(2) values of 7.9 and 7.0, respectively). The difference between both compounds could be explained in terms of the difference in the dissociation rate from the histamine H(1) receptor coupled to a putative low receptor reserve present in the rabbit bronchioles.
Simoen
V
V
Department of General Pharmacology, UCB SA, Chemin du Foriest, BE-1420 Braine l'Alleud, Belgium.
Christophe
B
B
D000818:Animals; D001980:Bronchi / Q000187:drug effects*; D017332:Cetirizine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000494:pharmacology*; D039563:Histamine H1 Antagonists, Non-Sedating / Q000494:pharmacology*; D066298:In Vitro Techniques; D008168:Lung / Q000473:pathology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology*; D011817:Rabbits
D039563:Histamine H1 Antagonists, Non-Sedating; D010879:Piperazines; C472067:levocetirizine; D006632:Histamine; D017332:Cetirizine