Affordable Access

Inhalation anaesthetic competition at high-affinity cocaine binding sites in rat brain synaptosomes.

Authors
  • Eckenhoff, R G
  • Fagan, D
Type
Published Article
Journal
British journal of anaesthesia
Publication Date
Dec 01, 1994
Volume
73
Issue
6
Pages
820–825
Identifiers
PMID: 7880673
Source
Medline
License
Unknown

Abstract

We have shown previously that inhalation anaesthetics inhibit dopamine transport in rat synaptosomes. In order to determine if this inhibition is associated with occupancy of the cocaine site, we examined binding of [3H] (2 beta-carbomethoxy-3 beta-(4-fluorophenyl)-tropane) (3H-CFT) in the presence of halothane or isoflurane 0.01-5 mmol litre-1 in rat brain synaptosomes. Both anaesthetics inhibited 3H-CFT binding (mean Ki 0.61 (SEM 0.12) and 0.75 (0.21) mmol litre-1, respectively), by increasing Kd (13.8 (0.6) and 29.8 (12.8) nmol litre-1, respectively) compared with control (8.02 (0.5) nmol litre-1) (P < 0.01). Halothane did not change Bmax, but isoflurane increased it significantly. Cocaine protected CFT sites from N-ethylmaleimide alkylation, but neither anaesthetic did. Photoaffinity labelling with halothane significantly inhibited 3H-CFT binding compared with UV-exposed controls. We conclude that clinically relevant concentrations of both anaesthetics inhibit high-affinity CFT binding, and the data suggest overlapping sites for halothane and CFT.

Report this publication

Statistics

Seen <100 times