K. Sandstrom et al., Effects of propofol on desipramine-sensitive [H-3]-noradrenaline uptake kinetics in rat femoral artery, ACT ANAE SC, 44(8), 2000, pp. 1011-1016
Citations number
30
Categorie Soggetti
Aneshtesia & Intensive Care","Medical Research Diagnosis & Treatment
Background: The intravenous anaesthetic propofol inhibits the neuronal upta
ke of noradrenaline (uptake(1)) from the vascular sympathetic neuromuscular
junction, resulting in an enhancement of the sympathetic neurotransmission
. This could be important for maintenance of blood pressure during propofol
anaesthesia. The aim of the present study was to determine how propofol in
fluences the kinetics of uptake(1).
Methods: Isolated segments of rat femoral arteries were incubated with [H-3
]-noradrenaline in the presence or absence of propofol and the radioactivit
y taken up was measured in a scintillation counter. The uptake, inhibitor,
desipramine, was used to delineate the specific neuronal uptake.
Results: Desipramine and 10 mu M propofol significantly reduced the uptake
in segments incubated with 0.1 mu M [3H]-noradrenaline. Propofol at 1 mu M
and 100 mu M did not affect the uptake. Non-linear regression analysis of s
pecific uptake yielded K-m 0.50 mu M, V-max 1.6 pmol mg(-1) 15 min(-1) and
Hill coefficient 1.1. Propofol (1-10 mu M) increased the K-m value and prop
ofol (10-100 mu M) increased the V-max value concentration-dependently, whi
le the Hill coefficient was not affected.
Conclusion: Propofol seems to have a biphasic effect on the uptake of norad
renaline in the vascular sympathetic neuromuscular junction. At lower propo
fol concentrations there is a decrease in the affinity of the noradrenaline
transporters. The resulting uptake inhibition is counteracted at higher pr
opofol concentrations by an increase in the efficacy of the uptake.