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Differences in GABAergic transmission between two inputs into the perirhinal cortex
Author(s) -
Garden Derek L. F.,
Kemp Nicola,
Bashir Zafar I.
Publication year - 2002
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1046/j.1460-9568.2002.02096.x
Subject(s) - perirhinal cortex , neuroscience , entorhinal cortex , gabaergic , inhibitory postsynaptic potential , neurotransmission , glutamatergic , hippocampus , agonist , chemistry , biology , psychology , temporal lobe , receptor , medicine , glutamate receptor , epilepsy
We have investigated properties of GABAergic synaptic transmission in perirhinal cortex evoked by stimulation of temporal and entorhinal cortex sides. GABA A IPSCs were isolated by blockade of glutamatergic transmission in slices of adult perirhinal cortex; IPSC decay was best fitted with two exponentials. Interestingly, temporal IPSCs had a larger slow component of decay ( P < 0.05) compared to entorhinal IPSCs. Depression of IPSCs by the GABA B receptor agonist baclofen was greater ( P < 0.05) in the temporal input (79 ± 4% depression) than the entorhinal input (65 ± 3% depression). Furthermore, baclofen abolished the slow component of IPSC decay in both inputs. Activity‐dependent depression of IPSCs at 5 Hz was greater ( P < 0.05) in the temporal input [paired pulse ratio (PPR) 0.5 ± 0.04] compared to that in the entorhinal input (PPR 0.67 ± 0.02, n = 10). The differences in paired pulse depression between the inputs were removed by the GABA B receptor antagonist CGP55845A. This study demonstrates several differences in GABA transmission between temporal and entorhinal inputs including the differential activation of presynaptic GABA B receptors and differential regulation of inhibitory synaptic transmission. These properties may be important in the control of neuronal activity within perirhinal cortex.