A Gao1 decapeptide modulates the hippocampal 5HT1A potassium current.
Oleskevich, Sharon.
Division of Neuroscience, John Curtin School of Medical Research,
Australian National University, Canberra, ACT 0200 AUSTRALIA.
APStracts 2:0281N, 1995.
SUMMARY AND CONCLUSIONS
1. The serotonin 1A (5HT 1A ) receptor is coupled to an inwardly rectifying
potassium current (I Kir ) via a G-protein. The identity of the G-protein
subtype was investigated with two 10-amino-acid peptides derived from the
carboxyl (C)-terminus of the [alpha] -subunits of the G o1 - and G i2 -
proteins (G ao1 and G ai2 ). The synthetic decapeptides were applied by
intracellular perfusion during whole cell recording from dentate granule cells
in the hippocampal slice preparation. 2. Bath application of 5HT produced an
I Kir which was blocked by the selective 5HT 1A receptor antagonist,
pindobind5HT 1A . The G ao1 peptide inhibited the 5HT 1A I Kir by 60 +/- 7%
while the G ai2 peptide had no effect. The G ao1 peptide produced a slowly
developing outward current which was not observed in the absence of peptide or
in the presence of the G ai2 peptide. 3. The results indicate that G ao1 and
not G ai2 modulates the 5HT 1A I Kir in hippocampal granule cells. They
further suggest that G ao1 occludes the 5HT 1A response by direct activation
of the I Kir . The intracellular perfusion of synthetic G a peptides provides
a new approach to identify the G-protein subtype(s) in a receptor-mediated
electrophysiological response.
Received 31 July 1995; accepted in final form 31 August 1995.
APS Manuscript Number J495-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.