Kinetics of serotonin uptake in the intact lung
- 47 Downloads
The pulmonary endothelium is capable of removing and metabolizing serotonin (5HT) carried in the venous blood. Thus the lungs can influence the arterial concentrations of 5HT. In addition, there is evidence that changes in the lung uptake of 5HT might portend more serious endothelial damage wherein the barrier function of the endothelium is compromised. This has been a stimulus for finding methods for evaluating these endothelial functions. These methods must be able to distinguish changes in whole organ function which result from changes in perfusion (e.g., cardiac output, redistribution of flow, etc.) from those resulting from changes in the function of the endothelial cells. When a bolus containing radio-labeled 5HT and an unmetabolizable indicator which is confined to the vascular space is injected into the pulmonary artery, the pulmonary venous or systemic arterial concentration curves contain information about both the convective transport and endothelial cell process involved. Some of this information can be interpreted quantitatively using a simple mathematical model.
KeywordsPulmonary endothelium Carrier-mediated transport Michaelis-Menten equation
Unable to display preview. Download preview PDF.
- 1.Bakhle, Y.S., J. Hartiala, H. Toivonen, and P. Uotila. Effects of cigarette smoke on metabolism of vasoactive hormones in rat isolated lungs.Br. J. Pharmacol. 65:485–499, 1979.Google Scholar
- 2.Bass, L., A.J. Bracken, and C.J. Burden. New approaches to uptake by heterogenous perfused organs: From linear to saturation kinetics, inLecture Notes in Biomathematics, Vol. 48, R.M. Lambrecht and A. Rescigno, eds. New York: Springer Verlag, 1983, pp. 120–121.Google Scholar
- 12.Gillis, C.N. and B.R. Pitt. The fate of circulating amines within the pulmonary circulation.Ann. Rev. Physiol. 44:269–281, 1982.Google Scholar
- 13.Gonzales-Fernandez, J. and S.E. Atta. Maximal substrate transport in capillary networks.Microvasc. Res. 5:180–198, 1973.Google Scholar
- 14.Junod, A.F. 5-Hydroxytryptamine and other amines in the lungs. InHandbook of Physiology, Section 3, The Respiratory System, Vol. 1, Circulation and Nonrespiratory Functions, A.P. Fishman and A.B. Fisher, eds. Bethesda: American Physiological Society, 1985, pp. 337–349.Google Scholar