1. Fenspiride is an anti-inflammatory agent that may have a role in reversible obstructive airways disease. Small, but significant, improvements have been seen in airways function and arterial oxygen tension in patients with mild chronic obstructive pulmonary disease. These changes have been attributed to the anti-inflammatory properties of the drug. However, airways function can be improved by other means, e.g. improved ventilation/perfusion ratio or reduced airways resistance. The possibility that fenspiride may have actions other than anti-inflammatory was investigated in two animal species. 2. In the rat, actions on the pulmonary circulation were investigated in the isolated perfused lung, but fenspiride proved to be a poor pulmonary vasodilator, showing only a small reversal of the raised pulmonary artery pressure induced by hypoxia. 3. Ventilation was measured in the anaesthetized rat using whole-body plethysmography. Fenspiride caused no increase in ventilation or changes in arterial blood gases. However, a profound hypotensive action was observed with high doses. 4. The possibility that a decrease in airways resistance ( R aw ) might occur with fenspiride was investigated in anaesthetized guinea pigs. Capsaicin (30 μmol/l) was used to increase baseline R aw through bronchoconstriction. Fenspiride gave a dose-dependent partial reversal of the raised R aw , and its administration by aerosol proved as efficacious as the intravenous route. In addition, the hypotensive side-effect found with intravenous injection was alleviated by aerosolized fenspiride. 5. An anti-bronchoconstrictor action of fenspiride could be one of the mechanisms involved in improving airways function and P ao 2 , seen in mild chronic obstructive pulmonary disease.

1. The effect of two structurally different platelet-activating factor (PAF) receptor antagonists, WEB 2086({3-[4-(2-chlorophenyl)-9-methyl-6 H -thieno[3,2- f ]-[1,2,4]-treazolo-[4,3- a ][1,4]-diazepine-2-yl]-1-(morpholinyl)-1-propanone}) and BN 52021, on hypoxic pulmonary vasoconstriction (HPV) was studied using an isolated rat lung preparation perfused with blood. 2. In lungs treated with WEB 2086 there was a dose-dependent attenuation of HPV, with complete abolition of HPV at the maximum dose. 3. Low doses of WEB 2086 caused only slight diminution of the pressor response to angiotensin II, although higher doses caused increasing attenuation of the angiotensin pressor response. 4. BN 52021 did not affect HPV. 5. Injection of PAF caused an increase in pulmonary artery pressure of 145%, a response abolished by pre-treatment of the lungs with either WEB 2086 or BN 52021. 6. These results suggest that PAF does not mediate HPV in the rat.

1. To determine the effects of age on the pulmonary circulation at rest and on exercise we analysed the results of right heart catheterization studies performed in 125 asymptomatic subjects aged 14-68 years, who were healthy or had indispositions which did not impair cardiac or pulmonary function. 2. Age accounted for less than 10% of total variation in resting values of right atrial, pulmonary artery and wedge pressures, and of cardiac output. 3. The pulmonary artery-wedge pressure gradient and flow resistance at rest significantly increased with age. 4. On exercise there were significant increases with age in right atrial, pulmonary artery and wedge pressures, pulmonary to wedge pressure gradient and flow resistance, but cardiac output was not influenced by age. 5. Pulmonary circulation variables at rest are mainly influenced by sex and size, but during exercise significant effects of age are apparent.

1. Dose-response curves for heart rate, cardiac output, arterial blood pressure and pulmonary artery pressure were obtained in 16 male patients after intravenous administration of three increasing doses of pindolol, propranolol or placebo. All patients had an uncomplicated acute myocardial infarction 6–8 months earlier. 2. The dose-response curves were obtained at rest and during repeated bouts of supine bicycle exercise. The cumulative dose amounted to 0.024 mg/kg body weight for pindolol and to 0.192 mg/kg body weight for propranolol. 3. At rest propranolol significantly reduced heart rate and cardiac output by 12% and 15% respectively. Arterial mean blood pressure was reduced by 9.2 mmHg. Mean pulmonary artery pressure increased significantly by 2 mmHg. Statistically significant changes in these variables were not seen after pindolol or placebo. 4. During exercise pindolol and propranolol both reduced cardiac output, heart rate and arterial blood pressure to the same extent. After propranolol mean pulmonary artery pressure was increased significantly by 3.6 mmHg. Pindolol and placebo did not change pulmonary artery pressure significantly. 5. The study suggests that pindolol may offer haemodynamic advantages over β-receptor-blocking agents without intrinsic sympathomimetic activity during low activity of the sympathetic nervous system, and may be preferable in situations where the β-receptor-blocking effect is required only during physical or psychic stress.

1. The chronic administration of minoxidil, 0024–0·212 mmol (5–40 mg) daily, to fifty-two severely hypertensive patients resulted in an average reduction of mean arterial pressure from 170 to 111 mmHg. 2. Haemodynamic studies in twelve of these patients indicated that the rise in pulmonary arterial pressure in patients without heart failure appears to be a direct result of a disproportionately large increase in cardiac output with respect to a relatively small decrease in pulmonary vascular resistance. Anti-hypertensive treatment of patients with congestive heart failure resulted in a decrease in mean pulmonary arterial pressure.