[Acute effects of platelet activating factor on the pulmonary circulation in rats]

To investigate the acute effects of platelet activating factor (PAF) on pulmonary circulation and cardiovascular function in rats, twenty anesthetized Wistar rats were given 100-800 ng/kg PAF by bolus intrapulmonary artery infusion. Mean pulmonary artery pressure (mPAP), mean systemic artery pressure (mSAP) and cardiac output (CO) were measured before and after administration. The results showed that PAF infusion caused: a rise in mPAP from 2.11 +/- 0.20 kPa to 2.65 +/- 0.11 kPa (100 ng/kg, P > 0.05), from 2.32 +/- 0.25 kPa to 2.85 +/- 0.24 kPa (200 ng/kg, P < 0.05) and from 2.11 +/- 0.33 kPa to 3.01 +/- 0.45 kPa (400 ng/kg, P < 0.05)p; a down in mSAP from 16.0 +/- 2.11 kPa to 9.1 +/- 2.39 kPa (100 ng/kg, P < 0.05); from 16.3 +/- 1.38 kPa to 7.0 +/- 0.57 kPa (200 ng/kg, P < 0.05) and from 16.4 +/- 2.56 kPa to 6.3 +/- 0.89 kPa (400 ng/kg, P < 0.05); and a down in CO from 48.1 +/- 2.16 ml/min to 30.8 +/- 3.27 ml/min (100 ng/kg, P < 0.05), from 47.8 +/- 2.12 ml/min to 25.6 +/- 2.86 ml/min (200 ng/kg, P < 0.05) and from 48.3 +/- 2.24 ml/min to 20.0 +/- 2.39 ml/min (400 ng/kg, P < 0.05). These findings suggested that PAF play an important role in the pathophysiologic course of pulmonary hypertension.