Functional state of corticostriatal synapses determines their expression of short‐and long‐term plasticity

G Akopian, W Musleh, R Smith, JP Walsh - Synapse, 2000 - Wiley Online Library
G Akopian, W Musleh, R Smith, JP Walsh
Synapse, 2000Wiley Online Library
Relationships between presynaptic function and short‐and long‐term plasticity were
investigated at adult corticostriatal synapses. Wide variability was observed in the
expression of short‐and long‐term synaptic plasticity. Intracellular records from 47 cells
produced 17 examples of LTD (< 90% of control), 10 examples of no long‐term change
(between 90–110% of control), and 20 examples of LTP (> 110% of control). Similar
variation existed in paired‐pulse and posttetanic plasticities. The variability expressed in all …
Abstract
Relationships between presynaptic function and short‐ and long‐term plasticity were investigated at adult corticostriatal synapses. Wide variability was observed in the expression of short‐ and long‐term synaptic plasticity. Intracellular records from 47 cells produced 17 examples of LTD (<90% of control), 10 examples of no long‐term change (between 90–110% of control), and 20 examples of LTP (>110% of control). Similar variation existed in paired‐pulse and posttetanic plasticities. The variability expressed in all three forms of plasticity appears to be related, based on correlations found between the paired‐pulse ratio (PPR) and tetanus‐induced short‐ (3 min posttetanus) and long‐term plasticities (16–20 min posttetanus). These data suggest that tetanus‐induced changes in synaptic strength are related to the intrinsic, preconditioned behavior of synapses. Every cell showing paired‐pulse depression also expressed LTD in response to high‐frequency activation of its afferents. Those synapses showing paired‐pulse potentiation tended to express LTP, although exceptions did exist. Similar relationships were found in a parallel analysis of population spikes. PPR also changed in association with the expression of posttetanic and long‐term depression. Greater paired‐pulse potentiation was observed in medial intracellular recordings, but no medial to lateral differences were seen in posttetanic plasticities. Field recordings also showed a medial bias toward paired‐pulse and posttetanic potentiation, but not in long‐term plasticity. Block of postsynaptic L‐type Ca2+ channels with nifedipine eliminated LTD expression, but overall no differences were found between nifedipine and control cells. Synapse 38:271–280, 2000. © 2000 Wiley‐Liss, Inc.
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