title: Blood gases and cardiovascular shunt in the South American lungfish (Lepidosiren paradoxa) during normoxia and hyperoxia.
abstract: The South American lungfish (Lepidosiren paradoxa) has an arterial P(O(2)) (Pa(O(2))) as high as 70-100 mmHg, corresponding to Hb-O(2) saturations from 90% to 95%, which indicates a moderate cardiovascular right to left (R-L) shunt. In hyperoxia (50% O(2)), we studied animals in: (1) aerated water combined with aerial hyperoxia, which increased Pa(O(2)) from 78+/-2 to 114+/-3 mmHg and (2) and aquatic hyperoxia (50% O(2)) combined room air, which gradually increased Pa(O(2)) from 75+/-4 mmHg to as much as 146+/-10 mmHg. Further, the hyperoxia (50%) depressed pulmonary ventilation from 58+/-13 to 5.5+/-3.0 mLBTPSkgh(-1), and Pa(CO(2)) increased from 20+/-2 to 31+/-4 mmHg, while pHa became reduced from 7.56+/-0.03 to 7.31+/-0.09. At the same time, venous P(O(2)) (Pv(O(2))) rose from 40.0+/-2.3 to 46.4+/-1.2 mmHg and, concomitantly, Pv(CO(2)) increased from 23.2+/-1.1 to 32.2+/-0.5 mmHg. R-L shunts were estimated to about 19%, which is moderate when compared to most amphibians.
authors.affiliation: Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes, 3900 Ribeirão Preto, SP, Brazil.
authors.forename: Mirian
authors.initials: M
authors.lastname: Bassi
authors.forename: Humberto
authors.initials: H
authors.lastname: Giusti
authors.forename: Glauber S
authors.initials: GS
authors.lastname: da Silva
authors.forename: Jalile
authors.initials: J
authors.lastname: Amin-Naves
authors.forename: Mogens L
authors.initials: ML
authors.lastname: Glass
mesh_terms: D000818:Animals; D001784:Blood Gas Analysis / Q000379:methods; D002319:Cardiovascular System / Q000503:physiopathology*; D005399:Fishes; D018496:Hyperoxia / Q000097:blood* / Q000503:physiopathology*; D010108:Oxyhemoglobins / Q000378:metabolism; D012123:Pulmonary Ventilation / Q000502:physiology*; D018709:Statistics, Nonparametric
chemical_list: D010108:Oxyhemoglobins