Kuzu İzole Pulmoner Arterlerinde Gelişen Hipoksik Pulmoner Vazokonstriksiyonda Gi ve Gs Proteinlerinin Rolü.

Hypoxic pulmonary vasoconstriction (HPV) is an intrapulmonary adaptive mechanism that matches alveolar ventilation to perfusion. However during prolonged alveolar hypoxia HPV occurs with many pulmonary diseases. Despite intensive studies, cellular mechanisms of HPV are still not well defined. G proteins are a family of membrane-associated proteins believed to be involved in the transduction of various signals including the regulation of vascular tonus. In this study, we aimed to determine the contribution of G; and Gs proteins in hypoxic vasoconstriction of lamb isolated pulmonary artery rings. Pulmonary arteries were isolated from left lower lobe of freshly slaughtered lamb. Arteries suspended in an organ bath filled with Krebs-Henseleit solution and isometric contraction recorded continuously via an isometric transducer connected to a computerised polygraphy system. The solution aerated with 75% N2- 20% O2- 5% Co2 (normoxic) and 95% N2- 5% Co2 (hypoxic) pO2 of bathing medium was measured continuosly using an oxygen electrode. Pertussis toxin and cholera toxin were used to investigate the role of Gs and Gs proteins. In the present study, we observed that hypoxia had no effect on resting force in large artery rings, but it caused a further contraction (1.7±0.5 mN/mm2, n=10) in 3 \xM 5-HT precontracted pulmonary arteries rings. Hypoxic vasoconstriction was inhibited by preincubation with 2 [ABSTRACT FROM AUTHOR]