P2RX3 Antibody

What is P2RX3 and what is its biological significance in research?

P2RX3 (also known as P2X3) is a purinergic receptor that functions as a ligand-gated ion channel activated by extracellular ATP. This receptor is predominantly expressed in nociceptive sensory neurons and plays a critical role in pain signaling pathways . P2RX3 is an extracellular ATP-activated non-selective cation channel that plays a particularly important role in sensory neurons where its activation is critical for gustatory, nociceptive responses, visceral reflexes, and sensory hypersensitization .

Recent research has expanded our understanding of P2RX3 function beyond pain perception to include roles in:

• Spiral ganglion neuron branching refinement during development

• Purinergic signaling in neuronal morphogenesis

• ATP-mediated calcium signaling via interaction with estrogen receptors

• Potential therapeutic target for chronic cough and pain management

The protein has a calculated molecular weight of 44 kDa but is commonly observed at 60-66 kDa in Western blots due to post-translational modifications .

What are the applications and recommended dilutions for P2RX3 antibodies?

P2RX3 antibodies are versatile tools for multiple research applications. Based on manufacturer recommendations and published literature, the following applications and dilutions are recommended:

It is recommended that each antibody be titrated in specific testing systems to obtain optimal results, as optimal dilutions may be sample-dependent .

What tissues and cells are appropriate positive controls for P2RX3 antibody testing?

When validating P2RX3 antibodies, selecting appropriate positive controls is crucial. Based on the literature and product documentation, the following samples provide reliable positive controls:

• Neural tissues:

  • Dorsal root ganglia (DRG) - particularly high expression in nociceptive neurons

  • Spiral ganglion neurons during developmental periods

  • Sensory neuron cultures from DRG

• Cell lines:

  • Jurkat cells (human T lymphocyte cell line)

  • PC12 cells (rat pheochromocytoma cell line)

  • K562 cells have been validated for Western blot applications

• Other tissues:

  • Human and mouse heart tissue - validated for IHC applications

  • Tissues with known sensory innervation (tongue, skin, visceral organs)

Immunohistochemical staining typically reveals P2RX3 expression in neuronal cell bodies, with both membrane and cytoplasmic distribution patterns depending on the epitope recognized by the antibody .

How can we distinguish between homomeric P2X3 and heteromeric P2X2/3 receptors using antibodies?

Distinguishing between homomeric P2X3 and heteromeric P2X2/3 receptors is challenging but crucial for understanding their differential functions. A methodological approach requires:

• Co-immunoprecipitation strategy:

  • Immunoprecipitate with P2RX3 antibody, then probe with P2X2 antibody

  • Run reverse co-IP with P2X2 antibody followed by P2RX3 detection

  • Include appropriate controls to validate specificity

• Dual immunofluorescence approach:

  • Use antibodies targeting unique epitopes of P2X2 and P2X3

  • Perform confocal microscopy to analyze co-localization patterns

  • Quantify co-localization coefficients to determine receptor composition

• Functional characterization complementation:

  • Combine antibody studies with electrophysiological recordings

  • Different functional effects may be observed depending on "homomeric or heteromeric composition of the target, its kinetic state, and the duration of antibody exposure"

• Selective pharmacological tools:

  • Use P2X3-selective antagonists (like those mentioned in search result ) alongside antibody detection

  • Compare effects on homomeric versus heteromeric receptor populations

• Knockout/knockdown validation:

  • Compare staining patterns in wild-type, P2X2-KO, and P2X3-KO tissues

  • Quantify changes in expression levels and distribution patterns

This multi-faceted approach offers the most reliable distinction between these receptor subtypes, which is essential for pain signaling research and drug development studies.

What factors affect the variability of P2RX3 detection in neural tissues?

Several factors can influence the variability of P2RX3 detection in neural tissues, requiring careful experimental design and interpretation:

• Developmental variation:

  • P2RX3 expression changes during development, being "expressed by Type I SGNs and hair cells during developmental periods that coincide with SGN branching refinement"

  • Age-matching of experimental animals is crucial for consistent results

• Anatomical specificity:

  • Expression levels vary between different DRG levels along the spinal cord

  • "Statistically significant difference between L1, L2, L4, and L6 levels for P2X3 receptors" has been reported

  • Standardize sampling locations across experiments

• Neuronal subtype heterogeneity:

  • Not all sensory neurons express P2RX3

  • Co-labeling with markers like "Calb2, Calb1, and Pou4f1" helps identify specific subpopulations

  • Loss of P2RX3 can affect the proportion of neuronal subtypes

• Sex differences:

  • "Interaction between P2X3 and membrane-associated ERα in primary sensory neurons may represent a novel mechanism to explain sex differences"

  • Include both sexes in experimental design and analyze data separately

• Technical considerations:

  • Fixation methods significantly impact epitope preservation

  • Antigen retrieval methods: "TE buffer pH 9.0" or "citrate buffer pH 6.0"

  • Different antibodies recognize distinct epitopes (extracellular vs. intracellular)

• Genetic background effects:

  • Knockout models show P2RX3 null mice have "SGNs with more complex branching patterns"

  • Strain differences may affect baseline expression levels

Standardization of tissue collection, processing, and staining protocols is essential for reducing variability in P2RX3 detection across experiments.

How should unexpected molecular weights be interpreted in P2RX3 Western blots?

P2RX3 Western blot results often show discrepancies between the calculated and observed molecular weights, which requires careful interpretation:

• Expected versus observed weight discrepancy:

  • Calculated molecular weight: "397 aa, 44 kDa"

  • Observed molecular weight: "66 kDa"

  • This 20+ kDa difference is consistent across multiple antibodies and samples

• Verification approach:

  • Confirm specificity with blocking peptide experiments

  • The antibody preincubated with its specific blocking peptide should eliminate the band

  • Compare results across multiple antibodies targeting different epitopes

  • Include P2RX3 knockout tissue as negative control

• Post-translational modifications:

  • Glycosylation is common for membrane proteins like P2RX3

  • Phosphorylation may contribute to shifts in apparent molecular weight

  • Treatment with glycosidases or phosphatases can confirm modification status

• Sample preparation effects:

  • Denaturation conditions affect membrane protein migration

  • Heat treatment duration can influence observed molecular weight

  • Reducing versus non-reducing conditions may yield different results

• Multimerization consideration:

  • Native P2RX3 functions as a trimer

  • Incomplete denaturation may result in detection of dimers or trimers

  • Sample buffer composition and heating duration are critical variables

• Isoform detection:

  • Alternative splicing may generate different P2RX3 isoforms

  • Multiple bands may represent different isoforms or degradation products

When reporting P2RX3 Western blot results, clearly document the observed molecular weight(s) and include appropriate controls to verify specificity.

What are the optimal approaches for quantifying P2RX3 expression changes?

Accurate quantification of P2RX3 expression requires methodological rigor:

• Western blot quantification:

  • Standardization protocol: "When the density in the control group was standardized to 1.0, the average densities were 0.172 ± 0.08 of ERαKO and 0.262 ± 0.10 of ERβKO in P2X3 receptors"

  • Use total protein normalization rather than single housekeeping genes

  • Confirm linear range of detection for accurate densitometry

  • Include standard curves with recombinant protein when possible

• Immunohistochemical quantification:

  • Cell counting approach: "The total numbers of DRG neurons expressing P2RX3 were counted"

  • Calculate percentage of P2RX3-positive neurons in defined fields

  • Use automated image analysis software for unbiased quantification

  • Include internal reference standards on each slide

• Fluorescence intensity measurements:

  • Standardize image acquisition parameters (exposure, gain, offset)

  • Use mean fluorescence intensity within defined regions of interest

  • Background subtraction must be consistent across all samples

  • Analyze raw, unprocessed images for accurate quantification

• qPCR complementation:

  • Validate protein-level changes with mRNA quantification

  • Design primers specific to P2RX3 with minimal cross-reactivity to other P2X family members

  • Use multiple reference genes for normalization

• Statistical analysis:

  • Perform power analysis to determine appropriate sample sizes

  • Use appropriate statistical tests based on data distribution

  • Report both raw values and normalized ratios

  • Include biological and technical replicates

• Controls for quantitative analysis:

  • Positive controls: known high P2RX3 expressors (e.g., DRG tissue)

  • Negative controls: P2RX3 knockout tissues or primary antibody omission

  • Concentration standards: dilution series of positive control samples

These approaches ensure reliable quantification of P2RX3 expression changes in experimental conditions, enabling accurate interpretation of results in pain signaling and neuronal development studies.

How can P2RX3 antibodies be optimized for co-localization studies with other neuronal markers?

Optimizing co-localization studies with P2RX3 and other neuronal markers requires careful experimental design:

• Antibody selection strategy:

  • Choose antibodies raised in different host species (e.g., rabbit anti-P2RX3 with mouse anti-neuronal marker)

  • Verify compatibility of fixation and retrieval conditions for all antibodies

  • Validate each antibody individually before combining them

• Neuronal marker considerations:

  • For subtype identification: "distribution of Type I SGN subtypes using antibodies that bind Calb2, Calb1, and Pou4f1"

  • For functional states: combine with activity markers (c-Fos, pERK)

  • For subcellular localization: pair with membrane or cytoskeletal markers

• Sequential staining protocol:

  • If using multiple antibodies from the same species:
    a. Apply first primary antibody at low concentration
    b. Detect with fluorophore-conjugated Fab fragment
    c. Block with excess unconjugated Fab
    d. Apply second primary antibody
    e. Detect with differently labeled secondary antibody

• Imaging optimization:

  • Use confocal microscopy with appropriate optical sectioning

  • Optimize pinhole settings to minimize out-of-focus light

  • Capture images at Nyquist sampling rate for optimal resolution

  • Include single-labeled controls to verify absence of bleed-through

• Quantitative co-localization analysis:

  • Calculate Pearson's correlation coefficient for intensity correlation

  • Use Mander's overlap coefficient to determine percentage overlap

  • Employ object-based analysis for discrete structures

  • Report co-localization statistics with appropriate statistical tests

• Common troubleshooting issues:

  • Cross-reactivity between secondary antibodies

  • Spectral bleed-through between fluorophores

  • Inadequate blocking causing non-specific binding

  • Photobleaching affecting quantification accuracy

This methodology enables reliable assessment of P2RX3 co-localization with other markers, providing insights into its functional interactions in sensory neurons.

What controls should be included when using P2RX3 antibodies for experimental validation?

Proper controls are essential for validating P2RX3 antibody specificity and ensuring reliable results:

• Specificity controls:

  • Blocking peptide validation: "Anti-P2X3 Receptor Antibody, preincubated with P2X3 Receptor Blocking Peptide"

  • Genetic models: P2RX3 knockout tissues show "significant" reduction in staining

  • Absorption controls: Pre-absorb antibody with recombinant P2RX3 protein

• Technical controls:

  • Primary antibody omission: Secondary antibody only to detect non-specific binding

  • Isotype controls: Irrelevant antibody of same isotype and concentration

  • Concentration series: Titration to determine optimal antibody concentration

• Positive tissue controls:

  • Known high expressors: "Positive WB detected in Jurkat cells" and "Positive IHC detected in human heart tissue"

  • Cross-species validation: Test in multiple species where reactivity is claimed

  • Previously validated samples: Include samples with established P2RX3 expression

• Negative tissue controls:

  • Known non-expressors: Tissues with minimal P2RX3 expression

  • Developmental stage controls: Early embryonic samples before P2RX3 expression

  • Knockdown validation: siRNA or shRNA treated samples

• Application-specific controls:

  • Western blot: Molecular weight markers to confirm band size (60-66 kDa)

  • IHC/ICC: Internal control tissues on the same slide

  • Flow cytometry: Unstained and secondary-only controls

• Reproducibility controls:

  • Technical replicates: Multiple sections/wells from the same sample

  • Biological replicates: Independent samples from different subjects

  • Antibody lot validation: Test new lots against previously verified lots

Documentation of these controls is essential for publication and should be included in materials and methods sections to demonstrate antibody validation rigor.

How can inconsistent P2RX3 immunostaining in neural tissues be troubleshooted?

Inconsistent P2RX3 immunostaining in neural tissues may result from multiple factors that require systematic troubleshooting:

• Fixation-related issues:

  • Optimization strategy: Test different fixation durations (10-30 minutes)

  • Fixative composition: 4% PFA in PBS at physiological pH (7.2-7.4)

  • Post-fixation processing: Cryoprotection and careful freezing for frozen sections

  • Antigen retrieval: "Suggested antigen retrieval with TE buffer pH 9.0; alternatively, antigen retrieval may be performed with citrate buffer pH 6.0"

• Antibody-related factors:

  • Epitope accessibility: Different antibodies recognize "extracellular" versus "intracellular, C-terminus" domains

  • Working concentration: Titrate antibody through recommended range (e.g., "1:50-1:500" )

  • Incubation conditions: Test both overnight 4°C and room temperature incubations

  • Antibody storage: Aliquot to avoid freeze-thaw cycles; store at -20°C

• Tissue-specific considerations:

  • Anatomical variation: "Statistically significant difference between L1, L2, L4, and L6 levels for P2X3 receptors"

  • Neuronal heterogeneity: Only specific subpopulations express P2RX3

  • Age/developmental stage: Expression changes during development

  • Species differences: Verify antibody reactivity for your species

• Detection system optimization:

  • Signal amplification: Consider tyramide signal amplification for weak signals

  • Secondary antibody selection: Use highly cross-adsorbed secondaries to minimize background

  • Chromogen development: Standardize development times for consistent results

  • Fluorophore selection: Choose bright, photostable fluorophores for immunofluorescence

• Systematic troubleshooting approach:

  • Test positive control tissues alongside experimental samples

  • Vary one parameter at a time to identify problematic steps

  • Document all protocol modifications for reproducibility

  • Compare results with published literature for expected staining patterns

These troubleshooting strategies should resolve most inconsistencies in P2RX3 immunostaining, leading to reliable and reproducible results in neural tissue studies.

How are P2RX3 antibodies used to study pain mechanisms and develop analgesic therapeutics?

P2RX3 antibodies are instrumental in pain research and therapeutic development:

• Mechanistic studies in pain models:

  • Expression analysis: P2RX3 upregulation in inflammatory and neuropathic pain models

  • Cellular localization: Predominantly in "nociceptive sensory neurons"

  • Protein-protein interactions: "Interaction between P2X3 and membrane-associated ERα" may explain sex differences in pain

  • Model validation: "The ethanol extract of Scutellaria baicalensis Georgi attenuates complete Freund's adjuvant (CFA)-induced inflammatory pain by suppression of P2X3 receptor"

• Therapeutic antibody development:

  • Function-modifying antibodies: "Monoclonal antibodies directed against human P2X3" can produce "distinct functional effects"

  • Potency assessment: "The most potent antibody, 12D4, showed an estimated IC50..." for inhibiting P2RX3 function

  • Subtype selectivity: Different effects on "homomeric or heteromeric composition of the target"

  • Duration of effect: Functional outcomes depend on "duration of antibody exposure"

• Drug development support:

  • Target validation: Confirm P2RX3 expression in target tissues

  • Compound screening: Antibodies used to verify binding sites of small molecule inhibitors

  • Mechanism of action studies: "Allosteric regulation of P2X3 in the inner pocket of the head domain (IP-HD)"

  • Safety assessment: Evaluate off-target effects in non-target tissues

• Translational research applications:

  • Human tissue validation: Antibodies reactive to "human, mouse, rat" enable cross-species comparison

  • Biomarker development: P2RX3 expression levels as potential pain biomarkers

  • Clinical correlation: Expression patterns in patient samples correlated with pain states

• Preclinical efficacy assessment:

  • Behavioral correlations: Linking P2RX3 expression to nociceptive behaviors

  • Compound efficacy: "Cough-suppressant molecule with nM affinity for hP2X3"

  • Taste alteration assessment: Testing compounds for "chronic cough relief by allosteric modulation of P2X3 without taste alteration"

This research area represents one of the most promising therapeutic applications of P2RX3 antibodies, with direct relevance to clinical development of pain and cough medications.

What role do P2RX3 antibodies play in studying neuronal development and circuit formation?

P2RX3 antibodies provide valuable insights into neuronal development and circuit formation:

• Developmental expression profiling:

  • Temporal patterns: "P2rx3 is expressed by Type I SGNs and hair cells during developmental periods that coincide with SGN branching refinement"

  • Spatial distribution: Expression changes across different neural tissues during development

  • Co-expression analysis: Relationship with other developmental markers

• Neuronal branching studies:

  • Branch refinement assessment: "P2rx3 null mice show SGNs with more complex branching patterns on their peripheral synaptic terminals and near their cell bodies around the time of birth"

  • Quantitative morphometry: Antibodies enable visualization of neuronal morphology for quantitative analysis

  • Recovery patterns: "Alterations in branching complexity appear to mostly recover by postnatal day (P)6"

• Neuronal subtype specification:

  • Fate determination: "P2rx3 null mice showed an increased proportion of SGNs that express Calb2"

  • Differentiation analysis: "P2rx3 may be necessary for normal Type I SGN differentiation"

  • Population studies: Distribution of neuronal subtypes using "antibodies that bind Calb2, Calb1, and Pou4f1"

• Circuit formation analysis:

  • Synaptic connectivity: P2RX3 involvement in forming "unramified synaptic contacts with inner hair cells"

  • Activity-dependent refinement: Potential role in spontaneous activity and synapse development

  • Target innervation: Analysis of SGN connections with hair cells during development

• Methodological approaches:

  • Genetic labeling strategies: "Using Sox2 CreERT2 and R26R tdTomato as a strategy to genetically label individual SGNs"

  • Antibody combinations: Co-labeling with developmental and subtype-specific markers

  • Time-course analysis: Examining P2RX3 expression at different developmental stages

This research area demonstrates how P2RX3 antibodies contribute to our understanding of the molecular mechanisms underlying neuronal development and circuit formation, with implications for developmental neurobiology and regenerative medicine.

How can P2RX3 antibodies be utilized to investigate purinergic signaling in non-neuronal tissues?

While P2RX3 is predominantly studied in sensory neurons, antibodies against this receptor are increasingly used to investigate purinergic signaling in non-neuronal tissues:

• Cardiovascular system applications:

  • Cardiac expression: "Positive IHC detected in human heart tissue"

  • Vascular studies: Potential role in vascular tone regulation

  • Cardiac conduction system: Investigation of purinergic signaling in specialized cardiac tissues

• Immune system investigations:

  • Lymphocyte expression: "Positive WB detected in Jurkat cells" (human T lymphocyte cell line)

  • Inflammatory regulation: Potential role in ATP-mediated inflammatory responses

  • Neuroimmune interactions: Cross-talk between P2RX3-expressing neurons and immune cells

• Urinary system research:

  • Bladder function: "P2RX3 is important for peripheral pain responses, and controls urinary bladder volume reflexes"

  • Mechanosensation: Role in detecting bladder distention via ATP release

  • Urinary disorders: Potential involvement in conditions like interstitial cystitis

• Methodological considerations:

  • Tissue-specific protocols: Optimize fixation and antigen retrieval for non-neural tissues

  • Positive controls: Include neural tissues as reference for antibody validation

  • Co-labeling strategy: Combine with tissue-specific markers to identify P2RX3-expressing cells

• Expression verification approaches:

  • Multi-method validation: Confirm antibody results with mRNA detection methods

  • Functional correlation: Correlate expression with ATP-evoked calcium responses

  • Pharmacological verification: Use selective P2RX3 modulators to confirm functional expression

• Cancer research applications:

  • Expression in cancer cell lines: K562, PC12, and other cell lines used in cancer research

  • Tumor microenvironment: Potential role in ATP-rich tumor environments

  • Pain mechanism: Investigation of cancer pain mediated by P2RX3 activation

These applications demonstrate the versatility of P2RX3 antibodies beyond their traditional use in neuroscience research, opening new avenues for investigating purinergic signaling across multiple organ systems and disease states.

What are the key differences between commercially available P2RX3 antibodies?

Researchers selecting P2RX3 antibodies should consider several distinguishing characteristics:

Comparison of epitope regions across antibodies:

• "Internal region AA 241-340/397"

• "AA 65-79 of rat P2X3 receptor (Extracellular)"

• "AA 383-397 of rat P2X3 receptor (Intracellular, C-terminus)"

Performance characteristics to consider:

• Observed molecular weight: Most consistently report "60-66 kDa" despite calculated MW of "44 kDa"

• Background levels in different applications

• Lot-to-lot consistency

• Publication track record: Some antibodies cite numerous publications supporting reliability

Select antibodies with validation data most relevant to your specific application and tissue of interest.

What are the optimal storage and handling practices for P2RX3 antibodies?

Proper storage and handling are critical for maintaining P2RX3 antibody performance:

• Storage conditions:

  • Temperature: "Store at -20°C. Stable for one year after shipment"

  • Formulation: Most supplied in buffer containing "PBS with 0.02% sodium azide and 50% glycerol pH 7.3"

  • Aliquoting: "Aliquoting is unnecessary for -20°C storage" for many formulations

  • Light protection: Essential for fluorophore-conjugated antibodies

• Handling best practices:

  • Avoid freeze-thaw cycles: Create working aliquots if multiple uses planned

  • Centrifuge briefly: Before opening to collect liquid at bottom of vial

  • Temperature transitions: Allow to equilibrate to room temperature before opening

  • Sterile technique: Use sterile pipette tips and tubes when handling

• Working dilution preparation:

  • Diluent selection: Use manufacturer-recommended diluent (often PBS with 1-5% BSA)

  • Prepare fresh: Make working dilutions on day of experiment when possible

  • Storage of diluted antibody: Maximum 1 week at 4°C for most diluted antibodies

  • Sodium azide: Low concentration (0.02%) may be added as preservative for diluted solutions

• Application-specific considerations:

  • Western blot: "Blocking and diluting buffer: 5% NFDM/TBST"

  • IHC/ICC: Dilute in buffer with appropriate blocking agent (serum, BSA)

  • Flow cytometry: Higher concentrations generally needed (e.g., "2.5μg" )

• Quality control practices:

  • Record lot numbers: Track performance across different lots

  • Positive control testing: Include known positive sample with each experiment

  • Periodic validation: Re-validate antibody performance if storage time extended

• Troubleshooting degradation signs:

  • Loss of signal intensity

  • Increased background staining

  • Unexpected bands or staining patterns

  • Precipitate formation in antibody solution

Following these guidelines will maximize antibody lifespan and ensure consistent, reliable results across experiments.