[Effects of ligustrazine and nitroglycerine on acute hypoxic pulmonary hypertension in anesthetized dogs].

The effects of ligustrazine and nitroglycerine on acute hypoxic pulmonary hypertension were observed in 10 anesthetized dogs. The results showed that ligustrazine (40 mg/kg) significantly reduced the hypoxic mean pulmonary artery pressure (PAPm) and pulmonary vascular resistance (PVR) the 10th and 15th minute after its injection into the right atrium, respectively. Its action was blocked by the continuous intravenous injection of methylene blue (1 mg/kg/min). It was suggested that the action of ligustrazine could be mediated by endothelium-derived relaxing factor. It was also discovered that nitroglycerine (40 micrograms/kg) could quickly decrease PAPm and PVR, indicating that nitroglycerine can be used to treat acute pulmonary hypertension and the aggravation of chronic cor pulmonale.