Effect of GNTI, a kappa opioid receptor antagonist, on MK-801-induced hyperlocomotion and stereotypy in mice.
Qi CT, Zou H, Zhang CH, Xie QL, Jin ML, Yu L.
Research Center for Biotechnology,
Shanghai Institutes for Biological Sciences,
Chinese Academy of Sciences,
Shanghai 200233, China.
Acta Pharmacol Sin. 2006 Nov;27(11):1401-8.


AIM: To examine the effect of GNTI [5'-guanidinyl-17-(cyclopropylmethyl)-6,7- dehydro-4,5alpha-epoxy-3,14-dihydroxy-6,7-2',3'-indolomorphinan], a selective antagonist for the kappa opioid receptor, in the MK-801 (dizocilpine maleate)-induced behavioral model of psychosis in schizophrenia as a way to explore the involvement of the kappa opioid receptor in modulating psychotic symptoms of schizophrenia. METHODS: Two doses of MK-801 (0.3 mg/kg and 0.6 mg/kg) were administered by systemic injection in mice to induce psychosis-like behavior as a rodent schizophrenia model, preceded by an injection of different doses of GNTI. Both locomotion and stereotypy were measured as the behavioral endpoints for quantitative analysis. RESULTS: GNTI inhibited MK-801-induced hyperlocomotion and stereotypy. In particular, GNTI showed differential modulation of stereotypy induced by 0.3 mg/kg vs 0.6 mg/kg MK-801. CONCLUSION: Antagonism of kappa opioid receptors attenuates MK-801-induced behavior, suggesting a potential involvement of the kappa opioid receptor in psychosis-like symptoms of schizophrenia. GNTI appears to be a useful pharmacological tool to explore the kappa opioid receptor function in vivo.
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