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ABSTRACT: Background and purpose
Lurasidone is an atypical mood-stabilizing antipsychotic with a unique receptor-binding profile, including 5-HT7 receptor antagonism; however, the detailed effects of 5-HT7 receptor antagonism on various transmitter systems relevant to schizophrenia, particularly the thalamo-insular glutamatergic system and the underlying mechanisms, are yet to be clarified.Experimental approach
We examined the mechanisms underlying the clinical effects of lurasidone by measuring the release of l-glutamate, GABA, dopamine, and noradrenaline in the reticular thalamic nucleus (RTN), mediodorsal thalamic nucleus (MDTN) and insula of freely moving rats in response to systemic injection or local infusion of lurasidone or MK-801 using multiprobe microdialysis with ultra-HPLC.Key results
Systemic MK-801 (0.5 mg·kg-1 ) administration increased insular release of l-glutamate, dopamine, and noradrenaline but decreased GABA release. Systemic lurasidone (1 mg·kg-1 ) administration also increased insular release of l-glutamate, dopamine, and noradrenaline but without affecting GABA. Local lurasidone administration into the insula (3 μM) did not affect MK-801-induced insular release of l-glutamate or catecholamine, whereas local lurasidone administration into the MDTN (1 μM) inhibited MK-801-induced insular release of l-glutamate and catecholamine, similar to the 5-HT7 receptor antagonist SB269970.Conclusions and implications
The present results indicate that MK-801-induced insular l-glutamate release is generated by activation of thalamo-insular glutamatergic transmission via MDTN GABAergic disinhibition resulting from NMDA receptor inhibition in the MDTN and RTN. Lurasidone inhibited this MK-801-evoked insular l-glutamate release through inhibition of excitatory 5-HT7 receptor in the MDTN. These effects on thalamo-insular glutamatergic transmission may contribute to the antipsychotic and mood-stabilizing actions of lurasidone.
SUBMITTER: Okada M
PROVIDER: S-EPMC6811777 | biostudies-literature | 2019 Oct
REPOSITORIES: biostudies-literature
British journal of pharmacology 20190915 20
<h4>Background and purpose</h4>Lurasidone is an atypical mood-stabilizing antipsychotic with a unique receptor-binding profile, including 5-HT<sub>7</sub> receptor antagonism; however, the detailed effects of 5-HT<sub>7</sub> receptor antagonism on various transmitter systems relevant to schizophrenia, particularly the thalamo-insular glutamatergic system and the underlying mechanisms, are yet to be clarified.<h4>Experimental approach</h4>We examined the mechanisms underlying the clinical effect ...[more]