Abstract
Channels were activated, in ripped-off patches from rat-cultured hippocampal neurons, by propofol alone, propofol plus 0.5 μM GABA (γ-aminobutyric acid) or GABA alone. The propofol-activated currents were chloride-selective, showed outward-rectification and were enhanced by 1 μM diazepam. The maximum propofol-activated channel conductance increased with propofol concentration from less than 15 pS (10 μM) to about 60 pS (500 μM) but decreased to 40 pS in 1 mM propofol. Fitting the data from 10 to 500 μM propofol with a Hill-type equation gave a maximum conductance of 64 pS, an EC50 value of 32 μM and a Hill coefficient of 1.1. Addition of 0.5 μM GABA shifted the propofol EC50 value to 10 μM and increased the maximum channel conductance to about 100 pS. The Hill coefficient was 0.8. The maximum channel conductance did not increase further when 1 μM diazepam was added together with a saturating propofol concentration and GABA. The results are compared to effects other drugs have on GABAA channels conductance.
Original language | English |
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Pages (from-to) | 75-82 |
Number of pages | 8 |
Journal | European Journal of Pharmacology |
Volume | 468 |
Issue number | 2 |
DOIs | |
Publication status | Published - 9 May 2003 |