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Effects of NMDA-R1 antisense oligodeoxynucleotide administration: behavioral and radioligand binding studies
A Zapata1, J L Capdevila, G Tarrason
1Departament de Bioanalítica Mèdica, CSIC, Barcelona, Catalonia, Spain.
Abstract:
The effects of an antisense phosphodiester oligodeoxynucleotide (ODN) directed to the NR1 subunit of the NMDA receptor mRNA and of its corresponding sense ODN were investigated in mice. Treatment with the antisense ODN significantly increased the time mice spent in the open arms of an elevated maze while the total number of arm entries was unaltered. Furthermore, seizure latencies after the administration of an ED100 dose of NMDA (150 mg/kg) were significantly higher in antisense treated animals compared to vehicle controls. At the same time, treatment with NR1 antisense ODN significantly reduced the Bmax of [3H]CGS-19755 binding (2101 fmol/mg protein) compared to both vehicle (2787 fmol/mg protein) and sense (2832 +/- 39 fmol/mg protein) controls without any significant change in KD (33 nM). A corresponding reduction of [3H]CGP-39653 binding was also observed after treatment with NR1 antisense compared to both sense and vehicle controls. In contrast, neither antisense nor sense ODNs altered the proportion of high affinity glycine sites or the potency of glycine at either high or low affinity glycine binding sites to inhibit [3H]CGP-39653 binding. These results show that in vivo treatment with NR1 antisense ODNs to the NMDA receptor complex reduces antagonist binding at NMDA receptors and has pharmacological effects similar to those observed with some NMDA receptor antagonists. These results also suggest that treatment with antisense ODNs may provide another means to investigate allosteric modulation of receptor subtypes in vivo.
Insights
Antisense oligodeoxynucleotides (ODNs) targeting the NMDA receptor NR1 subunit reduced antagonist binding and altered mouse behavior. This suggests ODNs can modulate NMDA receptor function in vivo.
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- The N-methyl-D-aspartate (NMDA) receptor is crucial for synaptic plasticity and neuronal function.
- NMDA receptor dysfunction is implicated in various neurological disorders.
- Antisense oligodeoxynucleotides (ODNs) offer a potential strategy for modulating gene expression and receptor function.
Purpose of the Study:
- To investigate the in vivo effects of antisense ODNs targeting the NR1 subunit of the NMDA receptor mRNA.
- To assess the impact of NR1 antisense ODN treatment on NMDA receptor antagonist binding and related behaviors in mice.
Main Methods:
- Administration of antisense and sense phosphodiester oligodeoxynucleotides (ODNs) to mice.
- Behavioral testing using an elevated plus maze to assess anxiety-like behavior.
- Assessment of seizure latency following NMDA administration.
- In vitro radioligand binding assays to quantify NMDA receptor antagonist binding (Bmax and KD).
Main Results:
- Antisense ODN treatment significantly increased time spent in open arms of the elevated plus maze, indicating reduced anxiety.
- Seizure latency was significantly prolonged in antisense ODN-treated mice.
- NR1 antisense ODN significantly reduced the Bmax of [3H]CGS-19755 and [3H]CGP-39653 binding, indicating decreased NMDA receptor antagonist binding sites.
- No significant changes were observed in the affinity (KD) of antagonist binding or in glycine binding sites.
Conclusions:
- In vivo treatment with NR1 antisense ODNs effectively reduces NMDA receptor antagonist binding.
- Antisense ODN-mediated modulation of NMDA receptors produces pharmacological effects similar to NMDA receptor antagonists.
- Antisense ODNs represent a valuable tool for investigating allosteric modulation of receptor subtypes in vivo.