Opioid analgesic tolerance, a root cause of opioid overdose and misuse, can develop through an associative learning. Despite intensive research, the locus and central pathway subserving the associative opioid analgesic tolerance (AOAT) remains unclear. Using a combination of chemo/optogenetic manipulation with calcium imaging and slice physiology, here we identify neuronal ensembles in a hierarchically organized pathway essential for AOAT. The association of morphine-induced analgesia with an environmental condition drives glutamatergic signaling from ventral hippocampus (vHPC) to dorsomedial prefrontal cortex (dmPFC) cholecystokininergic (CCKergic) neurons. Excitation of CCKergic neurons, which project and release CCK to basolateral amygdala (BLA) glutamatergic neurons, relays AOAT signal through inhibition of BLA μ-opioid receptor function, thereby leading to further loss of morphine analgesic efficacy. This work provides evidence for a circuit across different brain regions distinct for opioid analgesic tolerance. The components of this pathway are potential targets to treat opioid overdose and abuse.
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http://dx.doi.org/10.1126/sciadv.abo5627 | DOI Listing |
Psychopharmacology (Berl)
January 2025
Department of Psychology, University of New England, Biddeford, ME, USA.
Rationale And Objectives: In vivo receptor interactions vary as a function of behavioral endpoint, with key differences between reflexive and non-reflexive measures that assess the motivational aspects of pain and pain relief. There have been no assessments of D dopamine agonist / mu opioid receptor (MOR) agonist interactions in non-reflexive behavioral measures of pain. We examined the hypothesis that D/MOR mixtures show enhanced effectiveness in blocking pain depressed behaviors while showing decreased side effects such as sedation and drug reward.
View Article and Find Full Text PDFDrug Des Devel Ther
January 2025
Department of Anesthesiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China.
Purpose: To explore the postoperative opioid-sparing effect and incidence of adverse events of different dosages of intraoperative esketamine administration in patients undergoing laparoscopic gynecological surgery.
Patients And Methods: Patients undergoing elective gynecological laparoscopic operation was enrolled and randomly allocated to lower-dose esketamine group, higher-dose esketamine group, or control group. Patients in the two intervention groups received esketamine doses of 0.
J Crit Care Med (Targu Mures)
October 2024
"Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
Opioids represent one of the key pillars in postoperative pain management, but their use has been associated with a variety of serious side effects. Thus, it is crucial to investigate the timing and course of opioid administration in order to ensure a best efficacy to side-effect profile. The aim of our article was to investigate the analgesic effects of locally administered morphine sulfate (intraplantar) in a carrageenan-induced inflammation model in rats.
View Article and Find Full Text PDFPain Pract
February 2025
Department of Anesthesiology, University California San Diego, San Diego, California, USA.
Background: Nonthermal, pulsed shortwave (radiofrequency) therapy (PSWT) is a nonpharmacologic, noninvasive modality that limited evidence suggests provides analgesia. Its potential favorable risk-benefit ratio stems from its lack of side effects and significant medical risks, applicability to any anatomic location, long treatment duration, and ease of application by simply affixing it with tape. Even with a relatively small treatment effect, PSWT might contribute to a multimodal analgesic regimen, similar to acetaminophen.
View Article and Find Full Text PDFJ Anesth
January 2025
Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China.
Purpose: To examine the ramifications of both the modified and traditional subcostal anterior quadratus lumborum block (SQLB) on postoperative analgesia in individuals undergoing laparoscopic nephrectomy.
Methods: Forty-six individuals slated for elective laparoscopic nephrectomy under general anesthesia were randomly assigned to acquire either traditional or modified SQLB using 20 mL of 0.5% ropivacaine.
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