We have previously shown that L-DOPA is not just a dopamine precursor but also a neurotransmitter. Recently, a G-protein coupled receptor GPR143, a gene product of ocular albinism1, was identified as a receptor for L-DOPA. In the present study, we examined the effects of endogenous L-DOPA on anxiety-like behavior using GPR143-deficient mice (GPR143-KO). As a quantitative measure of anxiety-like behavior, we utilized the time spent in the open arm portion of the zero-maze test. Interestingly, GPR143-KO spent less time in open arm compared to wild-type mice (WT). Moreover, striatal indirect pathway-specific GPR143-KO mice spent less time in open arm compared to its control mice. Expression of GPR143-P2A-EGFP in the dorsomedial striatum of Gpr143-KO not influenced to anxiety-like behavior. Next, we used alpha-methyl-para-tyrosine (α-MPT), a synthetic inhibitor of L-DOPA. We confirmed that intraperitoneal administration of α-MPT at the dose of 3 mg/kg decreased the release of L-DOPA in the dorsal striatum, without affecting dopamine release. The administration of α-MPT decreased the time spent in open arm in WT, while this effect was not observed in GPR143-KO. Intraventricular administration of a synthetic peptide, which inhibited the interaction between GPR143 and dopamine D2 receptor, increased anxiety-like behavior in WT. These results suggest that L-DOPA inhibitory regulates anxiety-like behavior through interaction between GPR143 and dopamine D2 receptor in the striatal indirect pathway.