Dopamine and Morphine Tolerance

Dopamine Identified as Key Player

Our Mu Opioid Receptor antibody is used to show that blocking dopamine decreases morphine tolerance: Wen-Ling Dai, Feng Xiong, Bing Yan, Zheng-Yu Cao, Wen-Tao Liu, Ji-Hua Liu1, Bo-Yang Yu. Blockade of neuronal dopamine D2 receptor attenuates morphine tolerance in mice spinal cord. Scientific Reports 6, Article number: 38746 (2016). doi:10.1038/srep38746.

Images: (A) Double immunofluorescence staining showed that MOR (green) and D2DR (red) were co-localized in the mice spinal cord (20X magnification). Chronic morphine treatment increased the co-localization of MOR and D2DR in the spinal cord, and D2DR antagonist sulpiride (8 μg/10 μl, i.t.) reduced the increased co-expression of D2DR with MOR (n = 4). (B) Co-IP experiments showed that D2DR could interact with MOR, and the MOR/D2DR interactions were increased in the spinal dorsal horn after chronic morphine treatment for 7 days while D2DR antagonist sulpiride (8 μg/10 μl, i.t.) disrupted the interactions of the MOR/D2DR (n = 3).

Blockade of D2DR in spinal cord can disrupt the interactions between MOR and D2DR to attenuate morphine tolerance. These findings highlight the possibility of a new clinical strategy to prevent morphine antinociceptive tolerance.

More and More OR Pubs

Potent, Proven and Frequently Published

Many labs have used our Opioid Receptor antibodies over the past 10+ years. We are grateful for the many publications and testimonals referencing successful use of these antibodies.

Here's a sampling of more recent publications: Wendy M. Walwyn, Wenling Chen, Hyeyoung Kim, Ani Minasyan, Helena S. Ennes, James A. McRoberts, and Juan Carlos G. Marvizón. Sustained Suppression of Hyperalgesia during Latent Sensitization by μ-, δ-, and κ-opioid receptors and α_2A Adrenergic Receptors: Role of Constitutive Activity. The Journal of Neuroscience, 6 January 2016, 36(1): 204-221; doi: 10.1523/JNEUROSCI.1751-15.2016
...probed with antibodies to MOR (RA10104; Neuromics), p-Ser375-MOR (pMOR, RA18001; Neuromics) and p-Tyr416-Src family kinase (pSFK...serine-phosphorylated MOR (p-Ser375-MOR, RA18001; Neuromics) and a different MOR antibody (RA10104...
Jan Fraessdorf, Markus W. Hollmann , Iris Hanschmann, André Heinen, Nina C. Weber, Benedikt Preckel, Ragnar Huhn. Role of Endogenous Opioid System in Ischemic-Induced Late Preconditioning. Published: July 30, 2015DOI: 10.1371/journal.pone.0134283.
...Antibodies for μ-OR and δ-OR were purchased from Neuromics (Minneapolis, USA)...
Ying-Biao Chen, Fen-Sheng Huang, Ban Fen, Jun-Bin Yin, Wei Wang and Yun-Qing L nhibitory effects of endomorphin-2 on excitatory synaptic transmission and the neuronal excitability of sacral parasympathetic preganglionic neurons in young rat. Journal Name: Frontiers in Cellular Neuroscience, ISSN: 1662-5102, Article type: Original Research Article,Received on: 02 Apr 2015, Accepted on: 12 May 2015, Provisional PDF published on: 12 May 2015.
... guinea pig antiserum against MOR (1:1000, GP10106, Neuromics, Edina, Minnesota, USA)...
Sherika N. Smith, Candler Paige, Kandy T. Velazquez, Terika P. Smith, Srinivasa N. Raja, Steven P. Wilson, Sarah M. Sweitzer. Injury-specific promoters enhance herpes simplex virus mediated gene therapy for treating neuropathic pain in rodents. doi:10.1016/j.jpain.2014.12.007
...: MOR (Neuromics, RA10104, 1:1000)...

Figure: MOR in primary sensory neuron and its terminals were decreased in neuropathic mice. (A, B) Western blot shows that MOR protein were markedly decreased in sciatic nerve (A) and hindpaw skin (B) on day 7 after nerve injury when compared with sham-operated mice. The ratio of MOR/GAPDH in sham mice was set at 1 for quantifications. Zhou et al. Molecular Pain 2014, 10:51 http://www.molecularpain.com/content/10/1/51

We will continue to post information on our ORs.

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.

Mu Opioid Receptor, Aging and Immune Response

Mu Opioid Receptors (MOR) play an integral role in modulating perception of pain. Our Opioid Receptor and Opioid Neuropeptide Antibodies have been widely used and extensively published by Pain Researchers.

Here researchers determine a pivotal role of synaptic IGF-1R/Fyn signaling controlled by MOR downstream signaling cascades were crucial for the age-dependent neuroimmune modulation following traumatic stress: Hui Zhao, Xiaocong Zhao, Xiaoding Cao and Gencheng Wu. Age-Dependent Neuroimmune Modulation of IGF-1R in the Traumatic Mice. Immunity & Ageing 2012, 9:12 doi:10.1186/1742-4933-9-12.

Highlights: Fyn activity, as well as its molecular connection with IGF-1R was dependent on MOR, on account of that their coupling was obviously not able to be observed when lack of MOR, accordingly, there was not improvement from the immuno-suppression mediated by traumatic stress in MOR (−/−) mice. Likewise, there was not remarkable change in MOR expression, as well as the association of MOR with IGF-1R or Fyn in the synaptic zone. Then, it is plausible that a characteristic feature of IGF-1R was probably due to age-dependent Fyn activation that was triggered by MOR signaling cascades, this specialized process was mainly concentrated within synaptic zone and might contribute to the recovery from traumatic stress mediated immuno-suppression.

Images: MOR expression during traumatic stress. 2-month and 1-year mice were killed 1 and 3 days after traumatic stress (n = 5 for each group), synaptoneurosome from frontal cortex was prepared, Western blot analysis was used to detect MOR expression (A). Immunoprecipitation was used to analyze alterations of MOR and IGF-1R/Fyn interaction. The immunoprecipitation antibody was anti-Fyn (B) or anti-IGF-1R (D) and the immunoblotting antibody was anti-MOR. Panel C and E depict quantitative analysis of B and D respectively. Data are presented as percentage of control, values represent mean ± SD for 3 independent experiments. Con: control; T3: 3 days after trauma.

I will continue to post new applications for our MOR antibodies.

Opioid Receptor Antibodies Trifecta

This publication proposes a role for opioid receptors in treating cancers. It also references use of our μ, δ, and κ opioid receptor antibodies.

Kohei Yamamizu1, Sadayoshi Furuta, Shiori Katayama, Michiko Narita, Naoko Kuzumaki, Satoshi Imai, Hiroshi Nagase, Tsutomu Suzuki, Minoru Narita, and Jun K. Yamashita. The κ opioid system regulates endothelial cell differentiation and pathfinding in vascular development. Blood July 21, 2011 vol. 118 no. 3 775-785.

Highlights: The opioid system is, thus, a new regulator of vascular development that simultaneously modifies 2 distinct vascular properties, EC differentiation and vascular pathfinding. We confirmed that KOR, but not MOR, was highly expressed in various ECs such as HUVECs (data not shown), suggesting that KOR agonists could directly act on tumor ECs to suppress VEGF receptor expression, similar to the effects observed in embryonic ECs. If so, a combination therapy including an MOR agonist, morphine, and a KOR agonist (such as TRK820, a clinically approved drug in Japan for uremic pruritus) may prove useful for cancer therapy through the suppression of tumor angiogenesis by dual inhibition of VEGF ligands and receptors, extending the therapeutic benefits beyond pain relief.

Images: KOR was highly expressed in Flk1⁺ vascular progenitors. (A) RT-PCR showing mRNA expression of MOR, DOR, and KOR in ES cells, Flk1⁺ cells, cells after 1 or 3 days of Flk1⁺ cell culture (Flk-d1 or Flk-d3), CD31-positive cells (ECs) and CD31-negative cells (MCs) at Flk-d3. (B) Fluorescent staining for MOR, DOR, and KOR at Flk-d1. Nuclei are stained with DAPI (blue). Left, MOR; middle, DOR; right, KOR. Scale bars, 100 μm. (C) Double fluorescent staining for MOR, DOR, and KOR with CD31 (red) at Flk-d3. Nuclei are stained with DAPI (blue). Top, opioid (green) receptors (green); middle, CD31 (red); bottom, merged. Scale bars, 100 μm.

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.

Opioid Receptor Antibodies that Rock

We have Opioid Receptor Antibodies that work hard for our customers.

They are extensively referenced. We feature select publications and are pleased to feature the latest referencing staining of mouse neurons using our Kappa Opioid Receptor.

...Dominika Labuz, Yvonne Schmidt, Anja Schreiter, Heike L. Rittner, Shaaban A. Mousa and Halina Machelska. Immune cell–derived opioids protect against neuropathic pain in mice. J. Clin. Invest. doi:10.1172/JCI36246. Copyright © 2009, The American Society for Clinical Investigation...
...κ-opioid receptor (1:800, Neuromics)...

All Opioid Receptor Publications-Mu, Kappa and Delta

Published Reagents:
Mu Opioid Receptor-Rabbit
Mu Opioid Receptor-Guinea Pig
Delta Opioid Receptor 358-372
Kappa Opioid Receptor

Related Reagents:
Opioid Receptors
All Pain and Inflammation