scholarly journals Upregulation of μ-Opioid Receptor in the Rat Spinal Cord Contributes to the α2-Adrenoceptor Agonist Dexmedetomidine-Induced Attenuation of Chronic Morphine Tolerance in Cancer Pain

2020 ◽  
Vol Volume 13 ◽  
pp. 2617-2627
Author(s):  
Pinyi Zhang ◽  
Jianlong Bu ◽  
Xiaohong Wu ◽  
Lin Deng ◽  
Meng Chi ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Cancer Pain ◽  
Opioid Receptor ◽  
Morphine Tolerance ◽  
Rat Spinal Cord ◽  
Chronic Morphine ◽  
Α2 Adrenoceptor ◽  
Adrenoceptor Agonist ◽  
Μ Opioid Receptor

scholarly journals Dexmedetomidine Induces Microglial Activation and Modulates Microglial M1/M2 Polarization in Attenuation of Chronic Morphine Tolerance in Cancer Pain

2022 ◽  
Author(s):  
Jianlong Bu ◽  
Wu Xiaohong ◽  
Deng Lin ◽  
Ma Chao ◽  
Shi Xiaoding ◽  
...  
Keyword(s):  
Cancer Pain ◽  
Morphine Tolerance ◽  
Inflammatory Factor ◽  
Chronic Morphine ◽  
Protein Levels ◽  
M2 Polarization ◽  
Α2 Adrenoceptor ◽  
Adrenoceptor Agonist ◽  
Tnf Α ◽  
Anti Inflammatory

Abstract The pro-inflammatory (M1) and anti-inflammatory (M2) status of microglial determines the outcome of neuroinflammation, which contributes to the pathogenesis of chronic morphine tolerance. Studies report that α2-adrenoceptor agonist dexmedetomidine exerts anti-inflammatory effects in inhibiting morphine tolerance in normal and neuropathic pain animals, which has not been studied in cancer pain. Therefore, we investigate the effect of intrathecal DEX on morphine tolerance in cancer pain, and whether dexmedetomidine functions via modulating microglial activation and M1/M2 polarization. 54 Wistar rats with intrathecal catheterization were treated by morphine for 10 days. Test groups received intrathecal α2-adrenoceptor agonist dexmedetomidine or antagonist MK-467. The mRNA levels of TLR4 and NF-κB were tested by RT-PCR. The protein levels of TLR4, NF-κB, Iba-1, iNOS, CD206 were quantifed using Western blotting, and IL-10 and TNF-α were examined by ELISA. Dexmedetomidine attenuates mechanical threshold and thermal latency, and increased the expression of TLR4 and NF-κB in morphine tolerance of cancer pain. Dexmedetomidine attenuates mechanical and thermal nociception in morphine tolerance in cancer pain rats. Intrathecal DEX pre-treatment significantly increased the protein levels of microglia maker Iba-1, M2 marker CD206 and anti-inflammatory factor IL-10, while had no evident influence on the pro-inflammatory factor TNF-α and M1 marker iNOS in morphine tolerance. Our findings suggest that intrathecal dexmedetomidine attenuates morphine tolerance in cancer pain via α2-adrenoceptor pathway. Furthermore, dexmedetomidine upregulates TLR4/NF-κB pathway and induces microglia activation in chronic morphine tolerance of cancer pain. The anti-inflammatory effect of dexmedetomidine might be exerted by inducing microglia M2 polarization and increasing anti-inflammatory factor IL-10.

scholarly journals Absence of μ opioid receptor mRNA expression in astrocytes and microglia of rat spinal cord

Neuroreport ◽  
2012 ◽  
Vol 23 (6) ◽  
pp. 378-384 ◽  
Author(s):  
Sheng-Chin Kao ◽  
Xiuli Zhao ◽  
Chun-Yi Lee ◽  
Fidelis E. Atianjoh ◽  
Estelle B. Gauda ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Mrna Expression ◽  
Opioid Receptor ◽  
Rat Spinal Cord ◽  
Receptor Mrna ◽  
Μ Opioid Receptor

Novel function of bovine milk-derived lactoferrin on antinociception mediated by μ-opioid receptor in the rat spinal cord

2003 ◽  
Vol 965 (1-2) ◽  
pp. 239-245 ◽  
Author(s):  
Ken-ichiro Hayashida ◽  
Takashi Takeuchi ◽  
Hirohiko Shimizu ◽  
Kunio Ando ◽  
Etsumori Harada
Keyword(s):  
Spinal Cord ◽  
Opioid Receptor ◽  
Bovine Milk ◽  
Rat Spinal Cord ◽  
Μ Opioid Receptor

μ-Opioid receptor and α2-adrenoceptor agonist binding sites in the postmortem brain of heroin addicts

1994 ◽  
Vol 115 (1-2) ◽  
pp. 135-140 ◽  
Author(s):  
Ane M. Gabilondo ◽  
J. Javier Meana ◽  
Fernando Barturen ◽  
Magdalena Sastre ◽  
Jesús A. García-Sevilla
Keyword(s):  
Opioid Receptor ◽  
Binding Sites ◽  
Postmortem Brain ◽  
Agonist Binding ◽  
Heroin Addicts ◽  
Α2 Adrenoceptor ◽  
Adrenoceptor Agonist ◽  
Μ Opioid Receptor
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