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- Title
Reparatory effects of nicotine on NMDA receptor-mediated synaptic plasticity in the hippocampal CA1 region of chronically lead-exposed rats.
- Authors
Wang, Hui‐Li; Chen, Xiang‐Tao; Luo, Le; Lou, Zhi‐Yi; Wang, Shu; Chen, Ju‐Tao; Wang, Ming; Sun, Li‐Guang; Ruan, Di‐Yun
- Abstract
Activation of neuronal nicotinic acetylcholine receptors (nAChRs) modulates the induction of long-term potentiation (LTP): a possible cellular mechanism of learning. To investigate the effect of nicotine on synaptic plasticity in chronically lead-exposed rats, field excitatory postsynaptic potentials and paired-pulse facilitation (PPF) were recorded in the CA1 area of hippocampal slices from chronically lead-exposed 23–30-day-old rats. The results showed the following. (1) Nicotine (1 µm) facilitated the induction of LTP in CA1 by a weak tetanic stimulation (100 Hz, 20 pulses), which does not by itself produce LTP in lead-exposed rats. This effect was significantly suppressed by mecamylamine, a nicotinic antagonist, suggesting that the facilitation of LTP was through nAChRs. (2) The nicotine-facilitated LTP was blocked by dihydro-β-erythroidine (DHβE), a non-α7 nAChR antagonist, whereas long-term depression (LTD) was produced by the combination of nicotine and methyllycaconitine, a α7-nAChR antagonist. This type of LTD was blocked by DHβE. This suggested that several nAChR subtypes were involved in the nicotine-facilitated synaptic plasticity. (3) Nicotine enhanced PPF in the hippocampal CA1 region, and the nicotine-facilitated LTP in lead-exposed rats was blocked by eitherd-(–)-2-amino-5-phosphonopentanoic acid, the N-methyl-d-aspartate (NMDA) receptor antagonist, or picrotoxin, an antagonist of γ-aminobutyric acidA receptors. We suggest that nicotine-facilitated synaptic plasticity was due to the activation of NMDARs by disinhibition of pyramidal cells through presynaptic nAChRs. This may represent the cellular basis of nicotine-facilitated cognitive enhancement observed in chronically lead-exposed rats.
- Subjects
NICOTINE; NEUROPLASTICITY; HIPPOCAMPUS (Brain); CHOLINERGIC receptors; PICROTOXIN; RATS
- Publication
European Journal of Neuroscience, 2006, Vol 23, Issue 5, p1111
- ISSN
0953-816X
- Publication type
Article
- DOI
10.1111/j.1460-9568.2006.04645.x