Contractile endothelin-B (ETB) receptors in human small bronchi

摘要: Endothelins (ETs) are a family of novel regulatory peptides and various lines evidence suggest an important role for ETs in regulating pulmonary function. Two receptors endothelin, ETA ETB, have been found the human lung, according to recent studies non-ETA receptor seems mediate contraction large sized bronchi. Several emphasized importance small bronchi pathogenesis airway disease. In present paper, improved methodology was used which enables vitro down diameter 0.5-1.0 mm. Using new we tried further characterize this receptor. Small from distal parts bronchial tree were obtained tissue removed 15 patients with lung cancer. They dissected cut into ring segments, isometric tension recorded. ET-1, ET-2 ET-3 elicited strong concentration-dependent contractions bronchus. Basically, three equipotent about same maximal response. Upon reapplication, they all showed tachyphylaxis pattern, reaching half initial contraction. Comparative analysis IRL 1620, selective ETB agonist, revealed that effect agonist was, respects, similar responses induced by ETs. PD 145065, combined ETA/ETB antagonist competitively inhibited whereas FR139317, antagonist, without effect. conclusion, study shows accurate measurements can be made on data favour mediating endothelin-induced smaller than 1.0