Small Molecules/Peptides for Pain Researchers

Agonists, Antagonists, Inhibitors and Ligands

The roots of Neuromics is providing solutions for the study of nociceptive and neuropathic pain. Our tools are widely used and frequently published. We are pleased to bring you these small molecules designed to help you better understand the roots of pain and potential therapies.

Figure: Infarct volume after 3 days of reperfusion in the ipsilateral cortex and CP complex in male rats treated with vehicle saline (n=15) or 1 mg/kg per hour BRL 52537 (n=15) started at onset of reperfusion and continued for 22 hours (male-vehicle n=15; male-BRL n=15; mean±SEM). P<.0.05. Related Pub.

Name	Catalog #	Type	Size	Price
(±)-trans-ACPD	187-10	Agonist	10 mg 50 mg	$165 $665
(S)-4-Carboxyphenylglycine	323-10	Antagonist	10 mg 50 mg	$319 $1,319
2-APB	1224-10	Modulator	10 mg 50 mg	$99 $299
2-Methylthioadenosine triphosphate tetrasodium salt	1062-10	Agonist	10 mg	$299
AM 404	1116-10	Modulator	10 mg 50 mg	$119 $449
BAN ORL 24	3661-10	Antagonist	10 mg 50 mg	$183 $795
BRL 52537 hydrochloride	699-10	Ligand	10 mg 1 mg	$159 $609
CTAP	1560-1	Antagonist	1 mg	$135
Clocinnamox mesylate	898-2	Antagonist	2 mg	$179
Endomorphin-1	1055-5	Agonist	5 mg	$139
Endomorphin-2	1056-5	Agonist	5 mg	$139
FIT	1480-10	Agonist	10 mg 10 mg	$229 $929
N-Benzylnaltrindole hydrochloride	0754-10	Agonist	10 mg 10 mg	$199 $809
Nociceptin	910-1	Inhibitor	1 mg	$179
Nocistatin or NST	1198-1	Inhibitor	1 mg	$195

Questions? Do not hesitate to contact me @ pshuster@neuromics.com or 612-801-1007. Thank you! Pete Shuster, CEO and Owner, Neuromics.

Cytokines and Neuropathic Pain

I have been frequently posting results of testing blood serum of our clients suffering from Autoimmune (including Neuroimmuno) Diseases and Autistic Children. Our testing includes both standard medical testing (serum levels of toxins, metals, pathogen loads and markers like Cortisol, CRP, CDs, ALPS, NSE, S100b). In addition, we also doing testing using our Quantibody® Antibody.

Many of the clients report chronic mild to severe neuropathic pain.

By definition, this pain encompasses a series of heterogeneous conditions with some similar clinical manifestations. Peripheral examples include traumatic nerve injury, diabetic peripheral neuropathy and chemotherapy-induced peripheral neuropathy or Multiple Sclerosis. (see: Front Pharmacol. 2013; 4: 142.Published online Nov 22, 2013. doi: 10.3389/fphar.2013.00142). It is hard to unravel the cause and effects of this pain,

However, in analyzing the results from our clients' test we notice a relationship between dysregulation of some key cytokines and levels of pain (more data is required to confirm this). Here're our results (n=5)

Figure: Clients reporting pain vs healthy controls.

We will continue posting results here. We are releasing a Custom Quantibody Neuroimmuno-Pain Array which will include more bio-markers suspected to play a role in pain signaling.

More MOR Publications

Latest Mu Opioid Publications

Our Mu Opioid Receptor Antibodies have set the standard for the study of Pain Mechanisms. We have posted >40 publications referencing use of these antibodies.

Here's several published in 2014:

Charlie H.T. Kwok, Ian M. Devonshire, Andrew J. Bennett, Gareth J. Hathway. Postnatal maturation of endogenous opioid systems within the periaqueductal grey and spinal dorsal horn of the rat. PAIN - January 2014 (Vol. 155, Issue 1, Pages 168-178, DOI: 10.1016/j.pain.2013.09.0220. ...rabbit anti-MOR (Neuromics, Edina, MN, USA; 1:1000 with tyramide signal amplification protocol)...

Images: Immunohistochemical expression of opioid peptides and receptors in the DH (spinal cord dorsal horn) during postnatal development. (A) POMC (pro-opiomelanocortin) immunoreactivity in the dorsal horn in postnatal day (P)10, P21, and adult rats. White arrows depict where cell staining was found. Interestingly, fibre staining was also observed in the superficial dorsal horn (lamina I) of adult rats, but not in the younger ages. (B) Since both cell and fibre staining were observed, staining intensity was used to quantify the immunoreactivity of POMC in the DH. Quantified staining intensity for POMC in the DH significantly decreased as the animals aged, with highest immunoreactivity found at P10. (C) Enkephalin immunoreactivity in the DH was restricted to the superficial laminae and only fibre staining was observed. (D) Quantified staining intensity for enkephalin illustrate an age-dependent increase in immunoreactivity, which was highest at adult P10.(C) Enkephalin immunoreactivity in the DH was restricted to the superficial laminae and only fibre staining was observed. (D) Quantified staining intensity for enkephalin illustrate an age-dependent increase in immunoreactivity, which was highest at adult. (E) MOR (μ-opioid receptor) immunoreactivity in the DH, cell staining was found throughout the superficial and deeper laminae in all ages. (F) Cell count of MOR staining in the DH, which showed a significant increase as the animals aged (∗∗P<0 .01="" adult="" i="" p21="" vs="">


J. Desroches, J.-F. Bouchard, L. Gendron, P. Beaulieu. Involvement of cannabinoid receptors in peripheral and spinal morphine analgesia ☆ Neuroscience, Volume 261, 7 March 2014, Pages 23–42. http://dx.doi.org/10.1016/j.neuroscience.2013.12.030. ...The floating sections were then incubated in 1% sodium borohydride in PBS for 30 min, rinsed twice with PBS, and incubated for 30 min at room temperature in a blocking solution containing 3% normal goat serum (NGS) and 0.3% Triton X-100 in PBS. The sections were then incubated overnight at 4 °C with the guinea pig anti-MOP primary antibody (cat# GP10106; Neuromics, Minneapolis, MN, USA) diluted 1:1000 in the blocking solution. The floating sections were then washed in PBS and incubated with a goat anti-guinea pig secondary antibody conjugated with Alexa Fluor 488 (Molecular Probes, Invitrogen, Carlsbad, CA, USA) at a concentration of 1:1000 in PBS for 2 h at room temperature...

We will continue posting customer data and publications that give new insights into the mechanisms of pain.

Tissue Acidosis and Inflammation Related Nociceptive Pain

Important Implications for Inflammatory Pain States

Inflammatory pain is often accompanied by a drop in pH (Acidosis). Here investigators hypothesized that modest drops in extracellular pH leading to calcium fluxes acts like a dynamic switch to rapidly mobilize trkA to the cell membrane surface of adult sensory neurons, which in turn serves to increase the sensitivity of these neurons to NGF. The findings reveal a cellular mechanism whereby even small changes in pH can rapidly shift sensitivity to a critical driver of the inflammatory pain state—NGF. They way they demonstrate this shift is quite ingenious: Geoffrey E. Bray, Zhengxin Ying, Landon D. Baillie, Ruiling Zhai, Sean J. Mulligan, and Valerie M.K. Verge. Extracellular pH and Neuronal Depolarization Serve as Dynamic Switches to Rapidly Mobilize trkA to the Membrane of Adult Sensory Neurons. The Journal of Neuroscience, 8 May 2013, 33(19):8202-8215; doi:10.1523/JNEUROSCI.4408-12.2013.

Images: NGF-responsive adult sensory neurons have a large cytoplasmic pool of high-affinity NGF receptors. Six micrometer cryostat sections of L5 DRG processed for high-affinity NGF binding (left) or trkA immunohistochemistry (right) reveal a large cytoplasmic pool of proteins that are able to bind 20 pm radio-iodinated NGF with high affinity or that are immunoreactive to trkA-selective antibodies. Scale bar, 20 μm.

Here're images showing the pH Related switch and rapid migration of TrkA to the membrane

Images: Acidic pH challenge rapidly mobilizes trkA to the membrane from internal stores. A, Bar graphs summarize relative changes in neuronal cell-surface trkA expression from three separate experiments (detected with immunofluorescence) over neurons exposed to control (pH 7.4) or acidic (pH 6.5) media for 30 min with or without exposure to Golgi collapsing compound BFA and as normalized to the mean signal intensity from the control pH group. Note: A significant increase is observed in the mean levels of trkA mobilized to the neuronal membranes of sensory neurons in response to acidosis when compared with the control pH, a response that is blocked with BFA treatment. B, Immunofluorescence photomicrographs and summary histograms (C) depict degree of FM 1–43FX-stained neuronal membrane internalization in response to conditions as indicated. Note: Significant membrane internalization was only observed in the NGF challenge control group and not in response to acidic pH challenge with or without BFA treatment. (Data normalized to the control pH of each experimental condition and pooled from three separate experiments; A, C, one-way ANOVA with post hoc Tukey's, **< 0.01; ***< 0.001). Scale bar, 20 μm.

The heightened level of trkA activation likely has ramifications on both short- and long-term sensitization processes as it regulates the activity and expression of a wide variety of receptors, ion channels, and signaling molecules (Mantyh et al., 2011). In the short term, it modulates the activity of receptors and ion channels. For example, NGF decreases the threshold of activation of the nociceptive transient receptor potential vanilloid 1 (TRPV1) receptors (Chuang et al., 2001), mediates TRPV1 trafficking to the membrane (Stein et al., 2006), increases purinergic receptor P2X3-mediated currents and Ca²⁺ transients (D'Arco et al., 2007) and for sympathetic neurons, rapidly modulates the activity of at least four voltage-gated currents (Luther and Birren, 2009). In the long term, increased NGF can lead to increased transcription of many nociception-associated genes such as its receptors trkA and p75 (Verge et al., 1989, 1992); the neuropeptides Substance P, calcitonin gene-related peptide (Lindsay and Harmar, 1989; Verge et al., 1995), and PACAP; Jongsma Wallin et al., 2001, 2003); sodium channels (Dib-Hajj et al., 1998; Fjell et al., 1999; Kerr et al., 2001); and P2X3 (Ramer et al., 2001; Simonetti et al., 2006). It is also interesting to note that activation of trkA was linked in our study to a parallel activation of p38MAPK, which has been shown to be linked to NGF-mediated increases in ASIC3 expression during inflammation (Mamet et al., 2003).

Related Reagents:
All Trk Antibodies
Neurotrophin Antibodies
Neurotrophin Proteins
Primary Neurons and Astrocytes-Primary human, rat and mouse neurons and astrocytes by Category

P2X Receptor Markers-Pubs Update

2012 has been a record year for publications referencing use of our Purinergic Receptor Antibodies. These publications demonstrate use of these markers in a variety of assays and applications. Examples range from analysis of P2X2 expression in human bladder epithelial cells to showing P2X3 expressing nerve fiber boutons in rat horizontal spinal cord sections by immunofluorescence and much more.

Here's a summary of publications: F.C. Pradoa, D. Araldia, A.S. Vieiraa, M.C.G. Oliveira-Fusarob, C.H. Tambelia, C.A. Parada. Neuronal P2X3 receptor activation is essential to the hyperalgesia induced by prostaglandins and sympathomimetic amines released during inflammation. http://dx.doi.org/10.1016/j.neuropharm.2012.11.011. non-fat dry milk at room temperature, followed by incubation with P2X3 or PKCɛ rabbit polyclonal antibody (1:500; Neuromics) overnight at 4 °C, rinsed six times with TBST, and then incubated for 40 min in goat anti-rabbit IgG peroxidase conjugate...

Min Liu, PhD, MD, Yun-fei Xu, PhD, MD, Yuan Feng, PhD, MD, Fengqiang Yang, MD, Jun Luo, MD, Wei Zhai, PhD, MD, Jian-ping Che, MD, Guang-chun Wang, MD, Jun-hua Zheng, PhD. Epigallocatechin gallate attenuates interstitial cystitis in human bladder urothelium cells by modulating purinergic receptors. Journal of Surgical Research. http://dx.doi.org/10.1016/j.jss.2012.11.041
...P2X2 (Neuromics, Northfield, MN)...

Abeer W Saeed, Alfredo Ribeiro-da-Silva. Non-peptidergic primary afferents are presynaptic to neurokinin-1 receptor immunoreactive lamina I projection neurons in rat spinal cord. Molecular Pain 2012, 8:64 doi:10.1186/1744-8069-8-64Anna M.W. Taylora, Maria Osikowicza, Alfredo Ribeiro-da-Silva. Consequences of the ablation of nonpeptidergic afferents in an animal model of trigeminal neuropathic pain. PAIN. Volume 153, Issue 6, June 2012, Pages 1311–1319. http://dx.doi.org/10.1016/j.pain.2012.03.023.

Confocal images at high power obtained from horizontal spinal cord sections. In a confocal optical section from lamina I adjacent to the white matter (A), note the relatively abundant P2X3-IR fibers with varicosities (boutons). CGRP-IR fibers and boutons were considerably more abundant in this lamina. In a confocal optical section from inner lamina II (B), note the very high density of P2X3-IR fibers and varicosities, higher than that of CGRP-IR fibers in lamina I. Note that most varicosities display either P2X3 or CGRP immunoreactivity, although some co-localization is observed (yellow). Scale bar (A, B) = 20 μm.

T. Cho, V. V. Chaban. Interaction Between P2X3 and Oestrogen Receptor (ER)α/ERβ in ATP-Mediated Calcium Signalling In Mice Sensory Neurones. Journal of Neuroendocrinology Volume 24, Issue 5, pages 789–797, May 2012...with polyclonal rabbit antibody against P2X3 receptor (dilution 1 : 1000; Neuromics)...

Anna M.W. Taylora, Maria Osikowicza, Alfredo Ribeiro-da-Silva. Consequences of the ablation of nonpeptidergic afferents in an animal model of trigeminal neuropathic pain. PAIN. Volume 153, Issue 6, June 2012, Pages 1311–1319. doi.org/10.1016/j.pain.2012.03.023...Sections were then incubated for 48 hours at 4°C with a guinea pig polyclonal anti-P2X3 antibody (1:25,000; Neuromics, Edina, MN, USA), diluted in PBS-T. Following primary antibody incubation, sections were treated with a biotin-conjugated...

Ji Z-G , Ito S , Honjoh T , Ohta H , Ishizuka T , et al. 2012 Light-evoked Somatosensory Perception of Transgenic Rats That Express Channelrhodopsin-2 in Dorsal Root Ganglion Cells. PLoS ONE 7(3): e32699...guinea-pig anti-P2X3 (1:1,000, GP10108, Neuromics, Edina, MN, USA)...

Distribution of ChR2V in the dorsal part of the spinal cord. A–C. Immunohistochemical localization of ChR2V with the cell-type specific markers, NF200 (A), CGRP (B) or P2X3 (C). Scale bars indicate 40 µm. doi:10.1371/journal.pone.0032699.g003.

I will continue to post new publications and data in the coming year. Stay tuned. 

ASIC3 and Osteoarthritis

ASIC3 modulates pain and disease progression

Neuromics' foundation is built on providing reagents for pain researchers. I have posted the twists and turns via key publications and related data. Here's yet another success story with one of our Pain and Inflammation Research Antibodies.

Acid sensing ion channels (ASICs) are sodium-selective ion channels activated by low extracellular pH, and belong to the degenerin/epithelial Na+ channel superfamily. ASIC3  is the most sensitive to such a pH change [2,3], abundantly expressed in dorsal root ganglia (DRG) [4], and strongly correlated with pain. Here researchers show the role of ASIC3 in osteoarthritis: Masashi Izumi, Masahiko Ikeuchi, Qinghui Ji, Toshikazu Tani. Local ASIC3 modulates pain and disease progression in a rat model of osteoarthritis. Journal of Biomedical Science 2012, 19:77 doi:10.1186/1423-0127-19-77.
Highlights: OA was induced via intra-articular mono-iodoacetate (MIA) injection, and pain related behaviors were evaluated including weight bearing measured with an incapacitance tester and paw withdrawal threshold in a von Frey hair test. OA rats showed not only weight-bearing pain but also mechanical hyperalgesia outside the knee joint (secondary hyperalgesia). ASIC3 expression in knee joint afferents was significantly upregulated approximately twofold at Day 14. Continuous intra-articular injections of APETx2 inhibited weight distribution asymmetry and secondary hyperalgesia by attenuating ASIC3 upregulation in knee joint afferents. Histology of ipsilateral knee joint showed APETx2 worked chondroprotectively if administered in the early, but not late phase.

Images: Fast Blue labeling and immunohistochemistry staining for ASIC3 : (a-b) Naïve- model, (c-d) OA-model, (e-f) APETx2 administration to OA-model in early phase. Photos in each row are the same DRG. In (b),(d),(f), large arrows indicate Fast Blue labeled, ASIC3 immunoreactive (ASIC3-ir) DRG cells, while ASIC3-ir cells that were not labeled by Fast Blue are indicated by small arrowheads. More than 100 FB-labeled neurons were analyzed from 4 rats in each group. The percentage of ASIC3-ir knee joint afferents was 18 ± 3% (mean ± SD) in naïve models, 46 ± 4% in OA-models (p = 0.003), and 20 ± 5% in the early-phase APETx2 group (p = 0.006), respectively. Scale bar: 50 μm

Protocol: The [DRG] sections were blocked in 3% normal goat serum for 1 h, then incubated in primary antibody of ASIC3 (Neuromics; Edina, MN, GP 14015, 1:500) overnight in a humid chamber. The next day, the sections were incubated in the secondary antibody (Vector; Burlingame, CA, FI-7000, 1:500, FITC tagged) for 2 h. All antisera used were diluted in PBS containing 1% normal goat serum and 0.05% Triton X-100. Before, between, and after each incubation step, the sections were washed 3 times for 5 min in PBS. Finally, all sections were mounted with Vectashield (Vector, Burlingame, CA).
1. Waldmann R, Champigny G, Bassilana F, Heurteaux C, Lazdunski M: A proton-gated cation channel involved in acid-sensing. Nature 1997, 386:173–177. 2. Lingueglia E: Acid-sensing ion channels in sensory perception. J Biol Chem 2007, 282:17325–17329. note: see http://neuromics.net/weblog/post/tag/dr-eric-lingueglia/ for research using our siRNA transfectio reagent for ASIC3 gene expression analysis. 
3. Wemmie JA, Price MP, Welsh MJ: Acid-sensing ion channels: advances, questions and therapeutic opportunities. Trends Neurosci 2006, 29:578–586.
4. Voilley N, de Weille J, Mamet J, Lazdunski M: Nonsteroid anti-inflammatory drugs inhibit both the activity and the inflammation-induced expression of acid-sensing ion channels in nociceptors. J Neurosci 2001, 21:8026–8033.

TRPA1 and Tooth Pain

Our TRPV (Vanilloid); TRPM; TRPA and TRPCs have proven excellent for studying

Transient receptor potential ankyrin 1 (TRPA1) is activated by noxious cold (<17°C) and contributes to cold and mechanical hypersensitivity after inflammation and nerve injury: Yun Sook Kim, PhD, Hoon Kap Jung, DDS, Tae Kyung Kwon, DDS, Chin Soo Kim, DDS, PhD, Jin Hyun Cho, DDS, PhD, Dong Kuk Ahn, DDS, PhD, Yong Chul Bae, DDS, PhD.Expression of Transient Receptor Potential Ankyrin in Human Dental Pulp. Journal of Endodontics. Available online 8 June 2012. doi.org/10.1016/j.joen.2012.04.024.


Highlights: TRPA1 was expressed in a large number of axons branching extensively in the peripheral pulp and in a few axons within the nerve bundles in the core of the coronal pulp and in the radicular pulp. Under electron microscopy, TRPA1 immunoreactivity was typically localized near the plasma membrane of unmyelinated axons in the peripheral pulp, suggesting that in these axons it may act as a functional receptor. The proportion of axons expressing TRPA1 in neurofilament 200–positive axons significantly increased in the painful pulp compared with the normal pulp. TRPA1 was also densely expressed in the processes and the cell body of odontoblasts. A large number of axons coexpressed TRPA1 and Nav1.8.

Images: Immunofluorescent staining for (A) TRPA1 in the human normal dental pulp is completely abolished by (B) preadsorption with a control peptide, proving the specificity of the TRPA1 antiserum (×200, scale bars = 50 µm). doi.org/10.1016/j.joen.2012.04.024.

Related Reagents:

All TRP Antibodies                       
Pain and Inflammation Research Antibodies                     
Neurotransmission -Neurotransmission Research Antibody Categories

Primary Neurons and Astrocytes-Primary human, rat and mouse neurons and astrocytes

TRPV1, Gut Inflammation and Pain

"Where there's smoke there's fire" or in this study, where there's inflammation there is pain: Robert P. Watson, Elliot Lilley, Moh Panesar, Gurdip Bhalay, Steven Langridge, Shin-Shay Tian, Conor McClenaghan, Anna Ropenga, Fanning Zeng, Mark S. Nash. Increased prokineticin 2 expression in gut inflammation: role in visceral pain and intestinal ion transport. Neurogastroenterology & Motility. Volume 24, Issue 1, pages 65–e12, January 2012....Formalin-fixed, wax-embedded tissues with no overt signs of pathology were purchased from Asterand (Detroit, MI, USA); informed consent had been sought and received from all donors. All tissues were used in accordance with the Human Tissue Act 2004 (UK)...guinea pig anti-TRPV1 antibody (GP14100 – Neuromics, Edina, MN, USA)...

Images: expression of prokineticin receptors in human and rat tissues. (A) Immunohistochemical analysis of PKR1 expression in the myenteric and submucosal ganglia of human stomach, ileum, and colon. Pkr1 (B) and Pkr2(C) expression in a range of human tissues determined using qRT-PCR. (D, E) Immunohistochemical of PKR1 distribution in rat DRG showing an absence of expression in large diameter, NF200 positive neurons (D), but co-expression with TRPV1 in presumptive nociceptive sensory neurons (E). (F) Distribution of Pkr2 mRNA by in situ hybridization in rat DRG. The IHC/ISH images shown are representative of the data obtained from n = 3 donors/animals.



Key Results Prok2 gene expression was up-regulated in biopsy samples from ulcerative colitis patients, and similar elevations were observed in rodent models of inflammatory colitis. Prokineticin receptor 1 (PKR1) was localized to the enteric neurons and extrinsic sensory neurons, whereas Pkr2 expression was restricted to sensory ganglia. In rats, PROK2-increased intracellular calcium levels in cultured enteric and dorsal root ganglia neurons, which was blocked by Compound 3. Moreover, PROK2 acting at prokineticin receptors stimulated intrinsic neuronally mediated ion transport in rat ileal mucosa. In vivo, Compound 3 reversed intracolonic mustard oil-induced referred allodynia and TNBS-induced visceral hypersensitivity, but not non-inflammatory, stress-induced visceral pain.

Check out our Pain and Inflammation Research Antibodies.

TRPV1s in Action

Our TRPV1s continue to be widely used and published. This recent publication features use out TRPV1-C guinea pig polyclonal for immunohistochemistry and TRPV1-mouse specific for Western Blotting: Sarah E. Canetta, Edlira Luca, Elyse Pertot, Lorna W. Role, David A. Talmage. Type III Nrg1 Back Signaling Enhances Functional TRPV1 along Sensory Axons Contributing to Basal and Inflammatory Thermal Pain Sensation. PLoS ONE 6(9): e25108. doi:10.1371/journal.pone.0025108...IHC: TRPV1 (guinea pig, 1:1000, GP14100 Neuromics); WB: TRPV1 (rabbit, 1:1000, RA14113 Neuromics).

Figure. Sensory axons, but not soma, from Type III Nrg1+/− mice show reduced capsaicin responsiveness compared to axons from WT mice. (A) Representative traces of intracellular calcium along sensory axons in response to 1 µM capsaicin or 56 mM KCl. The change in intracellular calcium from baseline over time ([(F−F0)/F0]*100) is shown for WT (left) and Type III Nrg1+/− (right) axons. Hatched diagonal lines indicate where the time course was non-continuous. (B) Quantification of the maximum change in intracellular calcium in response to application of 1 µM capsaicin or 56 mM KCl by genotype. Averages of 5 animals per genotype were compared using a Student's t-test. Type III Nrg1+/− axons showed a significantly decreased response to capsaicin (p<0.05), but not to KCl, relative to WTs. Graph shows mean±SEM. (C) Type III Nrg1+/− sensory soma show normal response to capsaicin. Quantification of maximal change in fluorescence from baseline ([(F−F0)/F0]*100) in WT or Type III Nrg1+/− sensory neuron soma in response to 1 µM capsaicin or 56 mM KCl. Average responses from 4 WT and 4 Type III Nrg1+/− animals to application of capsaicin or KCl were compared by genotype using a Student's t-test. There was no statistically significant difference between genotypes. Graphs show mean±SEM. (D) Type III Nrg1 (green) and TRPV1 (red) are co-expressed along P21 WT cultured sensory neuron axons identified with a pan-axonal (PA) marker (blue). White arrows indicate examples where Type III Nrg1 and TRPV1 are in close proximity. Scale bar equals 10 µm. (E) P21 WT and Type III Nrg1+/− sensory neuron cultures have equivalent levels of total TRPV1 protein. Total TRPV1 protein measurement by immunoblot. The 95 kD TRPV1 band and the 35 kD GAPDH band are shown from a representative experiment comparing protein from P21 WT and Type III Nrg1+/− cultures. Quantification of fold change in intensity of TRPV1:GAPDH normalized to WT average. There was no statistically significant change in the ratio of TRPV1 to GAPDH between genotypes (WT, Type III Nrg1+/−, n = 3 animals). Genotype comparisons were made using a Student's t-test. Graph shows mean±SEM. doi:10.1371/journal.pone.0025108.g004
All TRPV1 Publications.

MOR and NMDAR Interplay-Implications in Pain Control

Our Opioid Receptor Antibodies continue to be referenced in publications by Pain Researchers. Many of these studies provide a greater understanding of how opioids alleviate pain and what modulates this ability.

For example, the capacity of opioids to alleviate inflammatory pain is negatively regulated by the glutamate-binding N-methyl-D-aspartate receptor (NMDAR). This study drills down into the specifics of this regulation and references use of Neuromics' MOR1C Antibody: María Rodríguez-Muñoz, Pilar Sánchez-Blázquez, Ana Vicente-Sánchez, Esther Berrocoso and Javier Garzón. María Rodríguez-Muñoz, Pilar Sánchez-Blázquez, Ana Vicente-Sánchez, Esther Berrocoso and Javier Garzón. The Mu-Opioid Receptor and the NMDA Receptor Associate in PAG Neurons: Implications in Pain Control. Neuropsychopharmacology , (3 August 2011) | doi:10.1038/npp.2011.155.

Abstract: The capacity of opioids to alleviate inflammatory pain is negatively regulated by the glutamate-binding N-methyl-D-aspartate receptor (NMDAR). Increased activity of this receptor complicates the clinical use of opioids to treat persistent neuropathic pain. Immunohistochemical and ultrastructural studies have demonstrated the coexistence of both receptors within single neurons of the CNS, including those in the mesencephalic periaqueductal gray (PAG), a region that is implicated in the opioid control of nociception. We now report that mu-opioid receptors (MOR) and NMDAR NR1 subunits associate in the postsynaptic structures of PAG neurons. Morphine disrupts this complex by protein kinase-C (PKC)-mediated phosphorylation of the NR1 C1 segment and potentiates the NMDAR–CaMKII, pathway that is implicated in morphine tolerance. Inhibition of PKC, but not PKA or GRK2, restored the MOR–NR1 association and rescued the analgesic effect of morphine as well. The administration of N-methyl-D-aspartic acid separated the MOR–NR1 complex, increased MOR Ser phosphorylation, reduced the association of the MOR with G-proteins, and diminished the antinociceptive capacity of morphine. Inhibition of PKA, but not PKC, CaMKII, or GRK2, blocked these effects and preserved morphine antinociception. Thus, the opposing activities of the MOR and NMDAR in pain control affect their relation within neurons of structures such as the PAG. This finding could be exploited in developing bifunctional drugs that would act exclusively on those NMDARs associated with MORs.

I will continue to post these studies. They give hope for pain sufferers as many propose potential new druggable targets.