The indium-113m-transferrin complex as an indicator of serotonin-induced vascular changes in the golden hamster lung.
In order to measure experimentally-induced lung microvascular permeability changes in small laboratory animals, a method using the radioactive indium-113m-transferrin complex as a macromolecular tracer was adopted for a model of anesthetized hamsters. Serotonin or saline were given either systemically (intravenously) or locally (intratracheally). The effects were studied with arterial blood pressure recordings, wet-dry weight determinations of lung tissue and in vitro gamma scintillation of the lungs. Intravenous injections of serotonin (100 resp 400 nmol/kg b.w.) reduced the lung content of indium-113m with a maximum of 74%, intratracheal instillations of serotonin (100, 400, greater than 4000 nmol/kg b.w.) reduced the indium-113m content ranging from 48% to 71%. Saline intratracheal instillation alone decreased indium-113m content by 53%. In all animals receiving serotonin there were decreases in blood pressure which was also the case, but to a lesser extent, in the animals receiving saline intratracheally. The water content of the lungs was not significantly affected in any group. We conclude that the indium-113m transferrin macromolecular tracer complex is a reproducible method for measuring vascular events. The results give additional proof that serotonin administered intravenously or intratracheally does not increase microvascular macromolecular permeability in the lung, but rather acts as a vessel constrictor and/or increases transmural pressure.
Hultkvist
U
U
Department of Zoophysiology, Lund, Sweden.
Bjellin
L
L
D000818:Animals; D001794:Blood Pressure; D002199:Capillary Permeability / Q000187:drug effects*; D006224:Cricetinae; D007205:Indium Radioisotopes; D007275:Injections, Intravenous; D008297:Male; D008647:Mesocricetus; D008833:Microcirculation / Q000187:drug effects; D011652:Pulmonary Circulation / Q000187:drug effects*; D012701:Serotonin / Q000494:pharmacology*; D014168:Transferrin; D014867:Water / Q000378:metabolism
D007205:Indium Radioisotopes; D014168:Transferrin; D014867:Water; D012701:Serotonin