CNQX disodium salt: Technical Guidance for Neuroscience Research

What This Product Solves

CNQX disodium salt (sodium 6-cyano-7-nitroquinoxaline-2,3-bis(olate)) is a high-affinity, competitive non-NMDA glutamate receptor antagonist, primarily targeting AMPA and kainate receptors. By inhibiting these receptors, it provides a tool for dissecting excitatory neurotransmission in neuronal systems, specifically in the context of glutamatergic signaling pathways. This compound is widely implemented in neuroscience research to investigate synaptic physiology, pain signaling modulation, and excitotoxicity mechanisms in the central nervous system. It is not suitable for experiments requiring NMDA receptor inhibition or for applications outside established glutamatergic models.

Protocol Parameters

Protocol Parameters

• assay: AMPA receptor inhibition | value_with_unit: IC₅₀ = 0.3 μM | applicability: Quantitative assessment of AMPA receptor-mediated currents in neuronal cultures or brain slices | rationale: Enables selective blockade of AMPA-mediated excitatory postsynaptic potentials | source_type: product_spec [product_url]
• assay: Kainate receptor inhibition | value_with_unit: IC₅₀ = 1.5 μM | applicability: Determining contribution of kainate receptors in synaptic transmission and excitotoxicity models | rationale: Provides quantifiable blockade of kainate-mediated responses for pharmacological dissection | source_type: product_spec [product_url]
• assay: Working solution preparation | value_with_unit: ≥27.6 mg/mL in DMSO | applicability: Preparation of concentrated stock solutions for experimental dosing | rationale: Ensures full solubility and stability for accurate dosing; ethanol and water are not suitable solvents | source_type: product_spec [product_url]
• assay: In vitro application concentration | value_with_unit: 20 μM | applicability: Persistent depolarization of thalamic reticular nucleus neurons in electrophysiological setups | rationale: Based on reported experimental usage for robust receptor inhibition | source_type: product_spec [product_url]
• assay: Storage conditions | value_with_unit: Room temperature, desiccated | applicability: Long-term solid storage to maintain compound integrity | rationale: Minimizes hydrolysis and degradation for reproducible results | source_type: product_spec [product_url]

Workflow Setup and QC Checklist

• Solubility Check: Dissolve CNQX disodium salt in DMSO at concentrations up to 27.6 mg/mL. Vortex and visually inspect to ensure no particulate matter remains. Avoid ethanol and water as solvents due to insolubility. [source_type: product_spec]
• Aliquoting and Storage: Prepare aliquots for single-use or short-term storage to avoid repeated freeze-thaw cycles. Store solid compound desiccated at room temperature; keep solutions at 4°C and use within several days. [source_type: product_spec]
• Receptor Targeting: Select experimental concentrations based on IC₅₀ values for AMPA (0.3 μM) and kainate (1.5 μM) receptor inhibition. For full inhibition, use concentrations several-fold above IC₅₀, but verify cell/tissue tolerance in pilot assays. [source_type: workflow_recommendation]
• Documentation: Record batch numbers, preparation date, and storage conditions in laboratory notebooks for traceability and reproducibility. [source_type: workflow_recommendation]
• APExBIO Reference: For detailed physicochemical data and handling guidance, consult the CNQX disodium salt product page. [source_type: product_spec]

Common Failure Modes and Fixes

• Incomplete Dissolution: If undissolved particles persist, warm the DMSO gently to room temperature and vortex vigorously. Do not use water or ethanol as substitute solvents; these will not yield usable stock solutions.
• Loss of Activity: Activity loss in working solutions can occur due to hydrolysis or repeated freeze-thaw. Mitigate by preparing fresh stocks as needed and minimizing solution exposure to ambient air and moisture.
• Precipitation in Aqueous Media: When diluting DMSO stocks into aqueous buffers, keep final DMSO concentration below 0.1% v/v to reduce precipitation, and add slowly with constant mixing.
• Batch Variability: Confirm each new batch's performance with a reference assay before full-scale experiments, especially if switching suppliers or lots.

Scope and Limitations

• CNQX disodium salt is validated for research on inhibition of excitatory neurotransmission via AMPA and kainate receptors. It is not indicated for NMDA receptor studies or for systems lacking these non-NMDA glutamate receptor subtypes. [source_type: product_spec]
• Solubility is restricted to DMSO; use in water or ethanol is not supported due to precipitation or insolubility. [source_type: product_spec]
• Solution stability is limited; only short-term use is recommended. Long-term storage of prepared solutions may compromise activity and reproducibility. [source_type: product_spec]
• For in vivo studies, experimental design should account for systemic distribution and potential off-target effects, as specific tissue selectivity cannot be assumed. [source_type: workflow_recommendation]

Conclusion

CNQX disodium salt is a rigorously characterized tool for selective inhibition of AMPA and kainate receptors in neuroscience research. Its use is grounded in well-defined physicochemical and pharmacological parameters, allowing for reproducible studies of glutamatergic signaling and related processes. Adhering to solubility, storage, and concentration guidelines—such as those detailed on the APExBIO product page—is essential for optimal performance. Users should remain within the documented scope to ensure data integrity and avoid common experimental pitfalls.