MORPHOLOGICAL AND PHYSIOLOGICAL STUDY OF THE EFFECT OF HISTAMINE ON THE ISOLATED PERFUSED RABBIT LUNG
Abstract
whether this is the re ult of an increased permea·
bility of the pulmonary circulation or only of the
bronchial circulation remains to be determined. In
order to selectively study the effect of histamine on
the pulmonary ciculation we used an isolated
perfused rabbit lung preparation because in this
species, the bronchial circulation is poorly developed.
Edema formation was assessed by continuously
monitoring the weight of the lung perfused at con-
stant pressure . These studies were supplemented by
electrn microscopic observations using hemoglobin
ultrastructural tracer for microvascular permeability.
We found that histamine (8.0 ~ µg / 100 ml
perfusate) did not cause lung weight to increase.
Ultrastructural studies showed that histamtine, at
this dosage, did not cause a greater leakage of hemo-
globin than occurred in the control lungs. Thus, we
have concluded that histamine does not increase the
permeability of the pulmonary microcirculation in
the isolated perfused rabbit lung.