In vitro response of tracheal smooth muscle from hyperresponsive guinea pigs to celiprolol.

BACKGROUND The use of beta-blockers is limited by adverse effects such as bronchospasm in asthmatics. Third generation beta-blockers such as celiprolol may show better respiratory tolerability because they lack beta-blocker induced broncho-constriction. METHOD Effect of celiprolol on the histamine induced contraction of tracheal muscle strips prepared from ovalbumin-sensitised guinea pigs was studied. Using oxygenated Krebs-Henseleit solution as the nutrient medium, the trachealis muscle activity was measured with isometric force displacement transducer and recorded on 4-channel Oscillograph. RESULT Celiprolol 10(-4) M shifted the concentration-response curve of histamine downwards and to the right. Mean of amplitude of contraction, percent responses and deviations when compared with the control group were significantly different (p < 0.05). CONCLUSION Celiprolol antagonised histamine-induced contractions of tracheal muscle of guinea pigs. So it may be considered safe in patients with asthma. However, further clinical evaluation and exploratory work is required.