The uptake of serotonin by the pulmonary endothelium is a saturable process which appears to be capable of transporting the serotonin against a concentration gradient. As long as the intracellular serotonin concentration is not too large the rate of return of metabolite is slow relative to the rate of uptake and it appears that transport into the cells is normally the rate limiting step in the disappearance of serotonin from the capillary blood. For the case of the serotonin uptake we have examined the behavior of the uptake kinetic parameters of the serotonin uptake we have examined the behavior of the uptake kinetic parameters Vmax (the maximum uptake rate) and Km (the capillary concentration at Vmax/2) obtained by fitting the data to a model based on the following hypotheses: 1) Serotonin uptake is unidirectional and can be represented by the Michaelis Menten equation. 2) The transport sites are homogeneously distributed per unit capillary surface area. 3) Flow in individual capillaries is plug flow. 4) Most of the bolus dispersion occurs upstream from the capillary bed.
ASJC Scopus subject areas
- Biomedical Engineering