Tramadol reduces the 5-HTP-induced head-twitch response in mice via the activation of mu and kappa opioid receptors.

Article Details

Citation

Copy to clipboard

Sun HL, Zheng JW, Wang K, Liu RK, Liang JH

Tramadol reduces the 5-HTP-induced head-twitch response in mice via the activation of mu and kappa opioid receptors.

Life Sci. 2003 Jan 31;72(11):1221-30.

PubMed ID

12570923 [ View in PubMed

]

Abstract

Tramadol, an atypical opioid analgesic, stimulates both opiatergic and serotonergic systems. Here we have investigated the effect of tramadol in mice on 5-hydroxyptrytophan (5-HTP)-induced head twitch response (HTR), which is an animal model for the activation of the CNS 5-HT(2A) receptors in mice. Tramadol attenuated 5-HTP-induced HTR in a dose-dependent manner as morphine. Furthermore, the nonselective opioid receptor antagonists, naloxone and diprenorphine (M5050), reversed the effect of tramadol on 5-HTP-induced HTR dose-dependently. Interestingly, in contrast to the selective delta opioid receptor antagonist NTI, beta-FNA, a selective mu receptor antagonist, and nor-BNI, a selective kappa opioid receptor antagonist, antagonized the attenuation of 5-HTP-induced HTR by tramadol. In conclusion, administration of tramadol systemically inhibits 5-HTP-induced HTR in mice by activating opiatergic system in the CNS. Our findings show that mu and kappa opioid receptors, but not delta opioid receptor, play an important role in the regulation of serotonergic function in the CNS.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Tramadol	Kappa-type opioid receptor	Protein	Humans	Unknown	Agonist	Details