Neuroscience 2003 Abstract
| Presentation Number: | 257.9 |
|---|---|
| Abstract Title: | Effect of GABAergic inhibition on pairing-induced plasticity in young adult CA1 hippocampus. |
| Authors: |
Paulsen, O.*1
; Meredith, R. M.1
1Dept. of Physiology, Univ. of Oxford, , United Kingdom |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Synaptic Plasticity -- Long-term potentiation (LTP) |
| Secondary Theme and Topics | Synaptic Transmission and Excitability<br />- Synaptic Transmission<br />-- Postsynaptic mechanisms: Inhibitory |
| Session: |
257. Synaptic Plasticity: Spike Timing & Plasticity Poster |
| Presentation Time: | Sunday, November 9, 2003 1:00 PM-2:00 PM |
| Location: | Morial Convention Center - Hall F-I, Board # C98 |
| Keywords: | LTP, HIPPOCAMPUS, DEVELOPMENT, INHIBITION |
Spike timing-dependent plasticity has been reported in hippocampal slice preparations from young animals and cultures (Bi & Poo, 1998; Debanne et al. 1998). We previously reported a developmental change in the induction rules for LTP in CA1 of hippocampal slices whereby with advancing age, a postsynaptic burst of action potentials became necessary for pairing-induced LTP (Meredith et al.,SFN abstract 2002). To investigate whether GABAergic inhibition plays a role in this change, we tested whether LTP induction in the adult hippocampus was affected by blocking GABAA receptor-mediated inhibition. Patch-clamp recordings were made from CA1 pyramidal neurons in submerged hippocampal slices (300µm) from young adult C57BL6 mice (5-8weeks old,25-27oC) in the presence of 10µM of GABAA receptor antagonist, gabazine. EPSPs were alternately evoked at 0.2Hz by two stimulation electrodes placed in stratum radiatum. After a stable baseline of 12-15 minutes, one afferent input was paired with a single postsynaptic action potential and later with a postsynaptic burst, each pairing repeated 30 times. EPSP amplitudes were monitored for 20 minutes after each pairing episode. In contrast to control conditions, single-spike pairing induced a significant potentiation of the test input in the presence of gabazine (263±29%,n=5,p<0.05). Subsequent burst-spike pairing induced a further but lesser increase in synaptic efficacy (142±13%,n=5,p<0.05). Small increases in control input amplitudes were observed following both pairing episodes but did not reach significance. A similar induction of LTP with single-spike pairing in adult mice was also observed in the presence of 5µM bicuculline methiodide. These results indicate that inhibitory activity has a significant effect on the induction rules for pairing-induced LTP in the adult hippocampus and thus, development of GABAergic inhibition may play an important role in governing the rules of synaptic plasticity in the mature brain.
Supported by EC FV Grant
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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