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To prove alpha1-adrenergic hypothesis for pulmonary hypertension we studied 6 patients aged 63.3 +/- 8 (range 50-75) years with stable, advanced chronic obstructive pulmonary disease (COPD), FEV=1.51 +/- 0.3 I and with pulmonary hypertension, mean pulmonary artery pressure 28.3 +/- 8 (range 21-40) mm Hg. a1 blocker, doxazosin was administered per os in a daily dose of 2-3 mg. Pulmonary hemodynamics was performed before and after 30 day of treatment. After therapy, compared to baseline results, pulmonary artery systolic pressure decreased from 48.6 +/- 14 to 42.5 +/- 13 mm Hg, p=0.003, pulmonary artery diastolic pressure from 14.5 +/- 6 to 7 +/- 4 mm Hg, p=0.02), mean pulmonary artery pressure from 28.3 +/- 8 to 21.1 +/- 5 mm Hg, p=0.01 and pulmonary vascular resistance from 389.6 +/- 14 to 234.6 +/- 73 dyn x s x cm5. No significant changes in pulmonary artery wedge pressure, cardiac output, arterial oxygen content, percent saturation of hemoglobin with oxygen and oxygen delivery were found. In summary, the results of 30 day doxazosin therapy support alpha1 adrenergic hypothesis for pulmonary hypertension and suggest potential clinical benefits during long term treatment in patients with pulmonary hypertension due to COPD.

Purpose: Glaucoma is the main cause of blindness in the developed countries. Its progress can be diminished by decreasing intraocular pressure (IOP) using pharmacological or surgical treatment. Antiglaucoma agents, alpha 2-adrenergic's receptor agonists have been known for several years as IOP lowering. Due to the fact that the majority of them turned out to be imidazoline receptor agonists, it is worth checking if selective imidazoline receptor (l1) agonists alter IOP. Preliminary animal experiments show that they lower IOP. In our study we examined the influence of rilmenidine, a potent l1 receptor agonist, on IOP in rabbits. Furthermore, we tried to find out whether l1 and alpha 2 receptor antagonists (efaroxan and rauwolscine) counteract the pharmacological effect of rilmenidine., Material and Methods: The study was conducted on adult male White New Zealand rabbits. All the substances were administered topically, and IOP was measured by applanation tonometry after topical anaesthesia before and 1, 3 and 5 hours after drug instillation., Results: Rilmenidine showed the lowering effect on IOP at the concentration of 0.4%. Efaroxan and rauwolscine partly inhibited rilmenidine effect., Conclusions: Rilmenidine is a potential antiglaucoma agent, though further studies are necessary.