Abstract

RODRIGUEZ, M; LAMANNA, V; ALFONSO, C  and  PEREZ-GONZALEZ, M. Efecto de la Hidralazina sobre la Vasoconstricción Pulmonar Hipóxica en la Arteria Pulmonar Principal de rata. RFM [online]. 2002, vol.25, n.1, pp.33-36. ISSN 0798-0469.

We studied the hypoxia-induced vasoconstriction (HVC) obteined in the rat pulmonary artery, and the effects induced on this response by verapamil (VE) and hydralazine (HZ). Rat pulmonary artery (PA) rings, 3 mm long, were superfused in vitro by a Kreb´s-Henseleit solution, 37° C and pH= 7,3-7,4, bubbled with 95% O₂, 5% CO₂. Basal tension was 2 g. After a stabilization period a contraction was induced by norepinephrine (NE), 3 x 10^-7 M. During the plateau the bubbling gas was changed to 95% N₂, 5% CO₂ and HVC was obteined. The preparation was allowed to relax in normal O₂ and HZ (5 x 10^-4 M) was added. After 30 minutes a new contraction was obteined with NE and then hypoxia. This HVC was significantly decreased in the presence of HZ, but not in the presence of VE (1 x 10^-6 M), following a similar protocol. Conclusion: HVC in the rat pulmonary artery is decreased significantly in the presence of HZ but does not change in the presence of VE.

Keywords : Pulmonary artery; Hypoxia; Vasoconstriction; Rat.