Dr. Collins et al., INDIRECT POTENTIATION OF SYNAPTIC TRANSMISSION BY METABOTROPIC GLUTAMATE RECEPTORS IN THE RAT HIPPOCAMPAL SLICE, Brain research, 684(2), 1995, pp. 165-171
The role that the metabotropic glutamate receptor plays in synaptic tr
ansmission is complex due to the multiple subtypes involved, which ini
tiate a number of intracellular mechanisms. Here we have investigated
the role of the metabotropic glutamate receptor in the induction of lo
ng-term potentiation (LTP). We have shown that, providing the CA3 regi
on remains attached to the slice, it is possible to induce potentiatio
n by bath perfusion of the metabotropic receptor agonist (1S,3R) 1-ami
nocyclopentane-1,3-dicarboxylic acid (ACPD) alone. The extent of the p
otentiation observed showed a strong negative correlation with the age
of the animal from which the slices were prepared. Perfusion of ACPD
was associated with an increase in the excitability of antidromically
activated CA3 neurones, the appearance of spontaneous burst firing wit
hin the CA3 region, and an increased fibre volley recorded in the CA1
region. Blockade of N-methyl-D-aspartate (NMDA) receptors prevented al
l these effects. We suggest that the ACPD-induced potentiation of CA1
fEPSPs is an indirect effect caused by spontaneous burst firing and/or
increased excitatory drive from CA3 neurones.