Bronchial circulation in the marsupial opossum, Didelphis marsupialis.
This study characterizes the existence of a bronchial circulation in a marsupial, an animal which does not undergo placental development and does not have a ductus arteriosus. Direct perfusion of the lung by the pulmonary vasculature during the fetal development of opossums may occur, potentially eliminating the need for a bronchial circulation. We used radio- and fluorescent-labeled microspheres in conjunction with postmortem intravascular casting to determine if opossums have a systemic (bronchial) blood supply to the lung (n = 9). Gross postmortem examination of the intravascular casts showed a well-developed common bronchial artery. The histological distribution pattern of fluorescent microspheres was primarily to the airways. A few fluorescent microspheres were observed in the alveolar capillaries, indicating that a precapillary bronchial-to-pulmonary anastomosis exists in the opossum. Using the reference flow technique, total bronchial blood flow to the left lung averaged 0.95 +/- 0.58 SE ml/min. The presence of a bronchial circulation in the opossum suggests that it is more than a vestigial structure from embryonic development, potentially supporting its functional importance for carrying nutrients to the airway.
Bernard
S L
SL
Department of Pulmonary and Critical Care Medicine, University of Washington School of Medicine, Seattle, USA. susan@colossus.pulmcc.washington.edu
Luchtel
D L
DL
Glenny
R W
RW
Lakshminarayan
S
S
D000818:Animals; D001775:Blood Circulation / Q000502:physiology; D001794:Blood Pressure; D001981:Bronchial Arteries / Q000033:anatomy & histology; D005456:Fluorescent Dyes; D008168:Lung / Q000033:anatomy & histology / Q000098:blood supply* / Q000254:growth & development; D008394:Marsupialia / Q000502:physiology; D008853:Microscopy; D008863:Microspheres; D009893:Opossums / Q000502:physiology*; D011652:Pulmonary Circulation / Q000502:physiology*
D005456:Fluorescent Dyes