Effect of drugs modulating serotonergic system on the analgesic action of paracetamol in mice.
OBJECTIVE
The underlying mechanisms for the analgesic action of paracetamol (PCT) are still under considerable debate. It has been recently proposed that PCT may act by modulating the Serotonin system. This study was conducted to verify the influence of Serotonin modulating drugs (buspirone, ondansetron, and fluoxetine) on the analgesic effect of PCT.


METHODS
Thirty adult albino mice were assigned to five groups: Normal saline, PCT, fluoxetine selective serotonin reuptake inhibitor (SSRI) + PCT, buspirone (5-HT1A Agonist) + PCT, and ondansetron (5HT3 antagonist) + PCT. Hot-plate and formalin test were used to determine pain threshold, tests being conducted 60 min after the last treatment. Statistical analysis was done using analysis of variance followed by Dunnet's test.


RESULTS
Coadministration of buspirone with PCT attenuated the antinociceptive activity of PCT (P < 0.001), whereas fluoxetine + PCT increased pain threshold in the hot-plate and formalin test (P = 0.0046). Analgesic effect of PCT was not affected by ondansetron in formalin models. It attenuated analgesic action of PCT in hot-plate test (P = 0.0137).


CONCLUSIONS
The results suggest that 5-HT1 receptors could also be responsible for the analgesic effect of PCT. Also, higher analgesia is produced by co-administration of SSRI (fluoxetine) + PCT.
Department of Pharmacology, Bharati Vidyapeeth Deemed University Medical College, Pune, Maharashtra, India.
Yogita S
YS
Karandikar
Department of Pharmacology, Bharati Vidyapeeth Deemed University Medical College, Pune, Maharashtra, India.
Peeyush
P
Belsare
Department of Pharmacology, Bharati Vidyapeeth Deemed University Medical College, Pune, Maharashtra, India.
Aditi
A
Panditrao
D000082:Acetaminophen / Q000494:pharmacology*; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D005260:Female; D008297:Male; D051379:Mice; D018490:Serotonin Agents / Q000494:pharmacology*
D000700:Analgesics; D018490:Serotonin Agents; D000082:Acetaminophen
Acetaminophen; antinociceptive acton; buspirone; fluoxetine; ondansetron; selective serotonin reuptake inhibitor; serotonin