Enhancement of endogenous release of glutamate and gamma-aminobutyric acid from hippocampus CA1 slices after in vivo long-term potentiation.
The effect of long-term potentiation (LTP) on endogenous amino acid release from rat hippocampus slices was studied. LTP was induced in vivo by application of a tetanus (200 Hz, 200 ms) to the Schaffer collateral fibers in unanesthetized rats. Endogenous release of glutamate and gamma-aminobutyric acid (GABA) was investigated 60 min after tetanization in CA1 subslices of potentiated and control rats. No significant effects of LTP were observed in basal and K(+)-induced Ca(2+)-independent release components of these amino acids. In contrast, K(+)-induced Ca(2+)-dependent release of both glutamate and GABA increased approximately 100% in slices from potentiated rats. No differences were observed in total content of glutamate and GABA between the subslices from control and LTP animals. These results suggest a persistent increase in the recruitment of the presynaptic vesicular pool of glutamate and GABA during LTP.
Ghijsen
W E
WE
Department of Experimental Zoology, University of Amsterdam, The Netherlands.
Besselsen
E
E
Geukers
V
V
Kamphuis
W
W
Lopes da Silva
F H
FH
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D004558:Electric Stimulation; D005971:Glutamates / Q000032:analysis / Q000378:metabolism*; D006624:Hippocampus / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000032:analysis / Q000378:metabolism*
D005971:Glutamates; D005680:gamma-Aminobutyric Acid; D011188:Potassium; D002118:Calcium