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The role of plasma protein binding in the inhibitory effect of nortriptyline on the neuronal uptake of norepinephrine
Author(s) -
Borgå Olof,
Hamberger Bertil,
Malmfors Torbjörn,
Sjöqvist Folke
Publication year - 1970
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt1970114581
Subject(s) - nortriptyline , incubation , endogeny , chemistry , inhibitory postsynaptic potential , norepinephrine , ultrafiltration (renal) , medicine , endocrinology , plasma concentration , human plasma , pharmacology , chromatography , biochemistry , biology , amitriptyline , dopamine
The inhibitory effect of nortriptyline (NT) on the neuronal uptake of radio labeled norepinephrine (NE) was studied with the use of the rat iris preparation in Krebs‐Ringer solution or human plasma. When added to the incubation medium, NT inhibited the uptake of NE approximately ten times as effectively in buffer as in human plasma within the tested concentration range of NT (10 −8 to 10 −6 M). This result is in good agreement with the 94 per cent binding (at NT concentration of 1.1 10 −6 M) obtained by the ultrafiltration method. Plasma from patients treated with NT also inhibited the uptake of NE. Correlation between the inhibitory effect and the “endogenous” plasma level of NT in the 14 patients studied was significant (p < 0.001). When NT was added in different concentrations to control plasma the inhibitory effect observed was close to that obtained with patient plasma containing the same “endogenous” concentration of NT.