Z. Xie et al., TETANUS-INDUCED POTENTIATION OF INHIBITORY POSTSYNAPTIC POTENTIALS INHIPPOCAMPAL CA1 NEURONS, Canadian journal of physiology and pharmacology, 73(12), 1995, pp. 1706-1713
In the present study, tetanus-induced potentiation of inhibitory posts
ynaptic potentials (IPSPs). previously described by our laboratory, wa
s further investigated in guinea pig hippocampal CA1 neurons. Tetanic
stimulation of the stratum radiatum induced a long-term potentiation o
f the excitatory postsynaptic potential and a potentiation of the gamm
a-aminobutyric acid A (GABA(A)) receptor mediated fast IPSP without en
hancing the GABA(B) receptor-mediated slow IPSP. During the potentiati
on, IPSPs evoked by stimulation of the alveus were unaffected. When sl
ices were superfused with DL-2-amino-5-phosphonovaleric acid (an N-met
hyl-D-aspartate, NMDA, antagonist) and 6-cyano-7-nitroquinoxaline-2,3-
dione (a non-NMDA glutamate antagonist), the potentiation of the monos
ynaptic fast IPSP could still be induced and maintained, suggesting th
at polysynaptic influences were unnecessary for this process. Finally,
since the potentiation was observed in CA1 neurons in which BAPTA or
K-252b was injected, this form of plasticity does not appear to be dep
endent on a rise in intracellular [Ca2+] or protein kinase C (PKC) act
ivity. These results indicate that tetanic stimulation of the stratum
radiatum induces a potentiation of GABAergic fast IPSPs in CA1 neurons
. The potentiation may be localized to the GABAergic synapse on CA1 ne
urons.