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. 1993 Mar;108(3):711–716. doi: 10.1111/j.1476-5381.1993.tb12866.x

The influence of the gamma 2L subunit on the modulation of responses to GABAA receptor activation.

A L Horne 1, P C Harkness 1, K L Hadingham 1, P Whiting 1, J A Kemp 1
PMCID: PMC1908038  PMID: 8385534

Abstract

1. Whole-cell patch clamp recordings were made from L-cells transfected with 2 combinations of subunits of the GABAA receptor. Log concentration-response curves were constructed to gamma-aminobutyric acid (GABA) on alpha 1,beta 1,gamma 2L containing cells and compared to those from alpha 1,beta 1 containing cells. The effects of flunitrazepam, pentobarbitone and alphaxalone on the concentration-response relationships were also examined. 2. From the log concentration-response curves, GABA had a mean (+/- s.e. mean) pEC50 = 5.2 +/- 0.09 and slope factor = 1.7 +/- 0.02 on alpha 1,beta 1,gamma 2L cells which were significantly different from the values obtained from alpha 1,beta 1 cells where the pEC50 = 5.6 +/- 0.02 and the slope = 1.5 +/- 0.02. 3. Flunitrazepam produced a parallel leftward shift of GABA concentration-response curves on alpha 1,beta 1,gamma 2L cells. The EC50 for flunitrazepam = 6.3 +/- 2.7 nM. No increase in the maxima of the GABA concentration-response curves was found in the presence of flunitrazepam. Flunitrazepam did not potentiate responses from alpha 1,beta 1 cells. 4. The log concentration-response curves from both populations of cells were shifted to the left by equal amounts by pentobarbitone. A significant increase in the maximal response to GABA was also produced by pentobarbitone. This occurred at lower concentrations of pentobarbitone on alpha 1,beta 1 cells. 5. Alphaxalone produced leftward shifts of GABA log concentration-response curves of similar magnitudes in both populations of cells.(ABSTRACT TRUNCATED AT 250 WORDS)

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Selected References

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