Effect of captopril, an angiotensin-converting enzyme inhibitor, on morphine analgesia and tolerance in rats, and elucidating the inflammation and endoplasmic reticulum stress pathway in this effect.

Creative Commons License

Taskiran A. Ş., Avci O.

Neuroscience letters, vol.741, pp.135504, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 741
  • Publication Date: 2021
  • Doi Number: 10.1016/j.neulet.2020.135504
  • Journal Name: Neuroscience letters
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED)
  • Page Numbers: pp.135504
  • Keywords: Captopril, Morphine analgesia, Morphine tolerance, Inflammation, Endoplasmic reticulum stress, BRAIN ANGIOTENSIN, NEUROPATHIC PAIN, ACTIVATION, RECEPTOR, SYSTEM, NEUROINFLAMMATION, POTENTIATION, APOPTOSIS, MEMORY
  • Sivas Cumhuriyet University Affiliated: Yes


The purpose of current study was to examine the possible involvement of captopril, an angiotensin-converting enzyme inhibitor, on nociception, morphine analgesia and morphine tolerance development involving inflammation and ER-stress pathways in rats. In this study, thirty-six male Wistar rats were used. Animals were divided into six groups: Saline, 50 mg/kg captopril, 5 mg/kg morphine, morphine + captopril, morphine tolerance and morphine tolerance + captopril. The resulting analgesic effect was measured with hot plate and tail flick analgesia tests. The dorsal root ganglions (DRG) tissues were collected for inflammation parameters, endoplasmic reticulum (ER) stress and apoptosis proteins by using ELISA. Captopril showed anti-nociceptive effect when given alone (p < 0.05 to p < 0.01). In addition, captopril increased the analgesic effect of morphine (p < 0.05 to p < 0.001) and also decreased the tolerance to morphine at a significant level (p < 0.05 to p < 0.001). However, it decreased inflammation and ER-stress when applied with single-dose morphine and tolerance induction (p < 0.001). Moreover, captopril decreased apoptosis proteins after tolerance development (p < 0.001). In conclusion, captopril has antinociceptive properties, increasing analgesic effect of morphine, and preventing tolerance development. These effects may occur by suppressing inflammation and ER-stress pathways.