STUDY OF THE ANTINOCICEPTIVE EFFECT OF MORPHINE EVALUATED BY A NEUROPATHIC PAIN MODEL IN MALE AND FEMALE MICE.

PEREZ V; BALERIO G. N

Paris

Congreso; 13th FENS Forum of Neuroscience; 2022

Morphine is one of the most widely used analgesics in the treatment of moderate and severe pain. However, its clinical use in chronic pain treatment is limited by the addictive potential. The co-administration of morphine with drugs that enhance the analgesic effect and reduce its reinforcing properties, could be an alternative in pain treatment with opioids.In the present study, we propose to determine the lowest effective dose of morphine to ameliorate the nociceptive threshold by using the partial sciatic nerve ligation (PSNL) in male and female Balb/C mice. Von Frey test (VFT) was performed in order to evaluate mechanical allodynia by calculating the nociceptive threshold. Mice were habituated to the environment for four days, baseline responses were measured, and surgery of the right paw was performed in a group of animals with PSNL (PSNL group), and surgery without PSNL was executed in another group (Sham group). Nine days after surgery, morphine (1, 3, 9 mg / kg, i.p.) or saline were administered and VFT was carried out. Our results showed that morphine (3 and 9 mg/kg) was able to reduce neuropathic pain in both sexes (p < 0.001). Although some studies have shown that the antinociceptive effect of morphine is more intense in males than in females, it has been suggested that sex differences depend on the strain of mice. These results will allow us to evaluate potential therapeutic targets to enhance the analgesic effect of opiates using the lowest effective dose of morphine (3 mg/kg) in both sexes.