Ru-Yin Tsai1, Yu-Che Cheng2, Chih-Shung Wong3. 1. Department of Nursing, Da-Yeh University, Changhua, Taiwan; Department of Anesthesiology, Cathay General Hospital, Taipei, Taiwan. 2. Department of Medical Research, Cathay General Hospital, Taipei, Taiwan. 3. Department of Anesthesiology, Cathay General Hospital, Taipei, Taiwan; School of Medicine, Fu-Jen Catholic University, New Taipei, Taiwan; Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan. Electronic address: w82556@gmail.com.
Abstract
BACKGROUND/ PURPOSE: Microglia have a crucial role in maintaining neuronal homeostasis in the central nervous system. Immune factors released from microglia have important roles in nociceptive signal transduction. Activation of microglia seems to be a shared mechanism in pathological pain and morphine tolerance because pharmacological attenuation of microglia activation provides satisfactory management in both situations. METHODS: In the present study, we investigated the effect of 1nM (+)-naloxone, which is not an opioid receptor antagonist, on morphine-induced activation of microglia EOC13.31 cells. RESULTS: Our results showed that 1μM morphine enhanced microglia activation and migration, decreased α-tubulin acetylation, and induced heat shock protein 90 (HSP90) fragmentation and histone deacetylase 6 (HDAC6) expression. Morphine-induced α-tubulin deacetylation and HSP90 fragmentation were HDAC6-dependent. Pretreatment with (+)-naloxone (1nM) inhibited morphine-evoked microglia activation and chemotaxis and prevented α-tubulin deacetylation and HSP90 fragmentation by inhibiting HDAC6 expression. CONCLUSION: Based on the findings of the present study, we suggest that (+)-naloxone inhibits morphine-induced microglia activation by regulating HDAC6-dependent α-tubulin deacetylation and HSP90 fragmentation.
BACKGROUND/ PURPOSE: Microglia have a crucial role in maintaining neuronal homeostasis in the central nervous system. Immune factors released from microglia have important roles in nociceptive signal transduction. Activation of microglia seems to be a shared mechanism in pathological pain and morphine tolerance because pharmacological attenuation of microglia activation provides satisfactory management in both situations. METHODS: In the present study, we investigated the effect of 1nM (+)-naloxone, which is not an opioid receptor antagonist, on morphine-induced activation of microglia EOC13.31 cells. RESULTS: Our results showed that 1μM morphine enhanced microglia activation and migration, decreased α-tubulin acetylation, and induced heat shock protein 90 (HSP90) fragmentation and histone deacetylase 6 (HDAC6) expression. Morphine-induced α-tubulin deacetylation and HSP90 fragmentation were HDAC6-dependent. Pretreatment with (+)-naloxone (1nM) inhibited morphine-evoked microglia activation and chemotaxis and prevented α-tubulin deacetylation and HSP90 fragmentation by inhibiting HDAC6 expression. CONCLUSION: Based on the findings of the present study, we suggest that (+)-naloxone inhibits morphine-induced microglia activation by regulating HDAC6-dependent α-tubulin deacetylation and HSP90 fragmentation.
Authors: Daniel R Kirkpatrick; Dan M McEntire; Tyler A Smith; Nicholas P Dueck; Mitchell J Kerfeld; Zakary J Hambsch; Taylor J Nelson; Mark D Reisbig; Devendra K Agrawal Journal: Expert Rev Clin Pharmacol Date: 2016-07-04 Impact factor: 5.045