Background: Surgeons need to prolong the duration of anesthesia and analgesia, in addition to preventing the release of pro-inflammatory factors in anticipation of post-operative disorders (POD). Objectives: To achieve the surgeons' goals mentioned above, melatonin was chosen as a pre-anesthetic agent.
Methods: For the purpose of testing the ability of melatonin to prolong the duration of anesthesia,24 adult rats were separated into (A (control), B, C and D). Group (A ) was treated with distilled water (D.W.) (2 ml / kg, orally), while groups (B, C and D) were treated with melatonin ( 20 mg/kg, orally) and after ( 0,15, 30, and 45) minutes, all groups were injected with (ketamine and xylazine). Formalin induced paw licking test was used to detect analgesic and anti-inflammatory effects of melatonin, animals in groups (A and B) (five/group) were injected with formalin into plantar surfaces of the rat's paw 45 minutes after treatment with either distilled water (A) or melatonin (B).
Results:Group (D) showed a significant prolongation of the duration of anesthesia compared to other groups (A, B, C).On the other hand, the formalin induced paw licking test revealed that melatonin has analgesic and anti-inflammatory effects represented in the significant delay in onset of paw licking accompanied by a significant decline in number of rats' attempts to lick their paws, both in the 1est phase (analgesia) and the 2end phase (anti-inflammatory) compared to the control group .
Conclusion: We conclude from our current study the possibility of using melatonin as a pre-anesthetic agent .