Selective effect of microembolization on pulmonary removal of biogenic amines.
Pulmonary amine extraction (E) was measured by triple-indicator dilution techniques from bolus injections of trace amounts of 5-hydroxy[14C]tryptamine ([14C]HT)m [3H]norepinephrine ([3H]NE), indocyanine green dye before and after glass-bead embolization in 23 anesthetized dogs. Control E(5-[14C]-HT) was 89.7 +/- 1.7%; 10 min after embolization (which approximately doubled pulmonary artery pressure and pulmonary vascular resistance), E(5-[14C]HT) was significantly reduced to 65.9 +/- 3.0% (kappa +/- SE; n = 10) (P less than 0.01). Control E([3H]NE) (40.1 +/- 4.5%) was unaffected by embolization. Imipramine (8 mg/kg) depressed control E(5-[14C]HT) to 38.7 +/- 1.5% and control E([3H]NE)d to 35.0 +/- 3.9% (P less than 0.05; n = 4). In these animals, pulmonary hemodynamic changes secondary to embolization were comparable to those in non-drug-treated dogs, but E(5-[14C]HT) and E([3H]NE) were not further depressed. Progressive pulmonary lobar artery ligation (n = 5) did not affect amine extraction until perfusion was limited to one lobe. The selectivity of the effect of embolization on E(5-[14C]HT), the lack of an effect on imipramine-insensitive E(5-[14C]HT) extraction, and the much smaller changes after progressive lobar ligation indicate that, although derecruitment of vascular surface area secondary to mechanical obstruction may contribute to postembolization depression of E(5-[14C]HT), additional mechanisms such as local saturation of 5-HT uptake or selective damage to endothelial cell transport of 5-HT may underlie these observations.
D000818:Animals; D001158:Arteries / Q000502:physiology; D001679:Biogenic Amines / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D004621:Embolization, Therapeutic; D006439:Hemodynamics / Q000187:drug effects; D007099:Imipramine / Q000494:pharmacology; D008026:Ligation; D008168:Lung / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D011652:Pulmonary Circulation; D012701:Serotonin / Q000378:metabolism; D014655:Vascular Resistance
D001679:Biogenic Amines; D012701:Serotonin; D007099:Imipramine; D009638:Norepinephrine