Pharmacological Research (May 2023)

Neural and molecular investigation into the paraventricular thalamic-nucleus accumbens circuit for pain sensation and non-opioid analgesia

  • Guangchao Zhang,
  • Mengqiao Cui,
  • Ran Ji,
  • Shiya Zou,
  • Lingzhen Song,
  • Bingqian Fan,
  • Li Yang,
  • Di Wang,
  • Suwan Hu,
  • Xiao Zhang,
  • Tantan Fang,
  • Xiaolu Yu,
  • Jun-Xia Yang,
  • Dipesh Chaudhury,
  • He Liu,
  • Ankang Hu,
  • Hai-Lei Ding,
  • Jun-Li Cao,
  • Hongxing Zhang

Journal volume & issue
Vol. 191
p. 106776

Abstract

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The paucity of medications with novel mechanisms for pain treatment combined with the severe adverse effects of opioid analgesics has led to an imperative pursuit of non-opioid analgesia and a better understanding of pain mechanisms. Here, we identify the putative glutamatergic inputs from the paraventricular thalamic nucleus to the nucleus accumbens (PVTGlut→NAc) as a novel neural circuit for pain sensation and non-opioid analgesia. Our in vivo fiber photometry and in vitro electrophysiology experiments found that PVTGlut→NAc neuronal activity increased in response to acute thermal/mechanical stimuli and persistent inflammatory pain. Direct optogenetic activation of these neurons in the PVT or their terminals in the NAc induced pain-like behaviors. Conversely, inhibition of PVTGlut→NAc neurons or their NAc terminals exhibited a potent analgesic effect in both naïve and pathological pain mice, which could not be prevented by pretreatment of naloxone, an opioid receptor antagonist. Anterograde trans-synaptic optogenetic experiments consistently demonstrated that the PVTGlut→NAc circuit bi-directionally modulates pain behaviors. Furthermore, circuit-specific molecular profiling and pharmacological studies revealed dopamine receptor 3 as a candidate target for pain modulation and non-opioid analgesic development. Taken together, these findings provide a previously unknown neural circuit for pain sensation and non-opioid analgesia and a valuable molecular target for developing future safer medication.

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