VU0364770 (VU 0364770)(EC50=1.1 μM), a positive allosteric modulator(PAM) of mGlu4, shows insignificant activity at 68 other receptors, including other mGlu subtypes.

VU0364770 is a potent and effective positive allosteric modulator of mGlu4. VU0346770 exhibits a potency of 1.1 ± 0.2 μM at human mGlu4 in the presence of an EC20 concentration of glutamate and shifts the glutamate concentration-response curve 31.4 ± 4.0-fold to the left. VU0364770 exhibits a potency of 290 ± 80 nM at rat mGlu4 and induces an 18.1 ± 1.7-fold left shift of the glutamate concentration-response curve. [1]

VU0364770 shows efficacy alone or when administered in combination with l-DOPA or an adenosine 2A (A2A) receptor antagonist preladenant currently in clinical development. When administered alone, VU0364770 exhibits efficacy in reversing haloperidol-induced catalepsy, forelimb asymmetry-induced by unilateral 6-hydroxydopamine (6-OHDA) lesions of the median forebrain bundle, and attentional deficits induced by bilateral 6-OHDA nigrostriatal lesions in rats. In addition, VU0364770 enhances the efficacy of preladenant to reverse haloperidol-induced catalepsy when given in combination. The effects of VU0364770 to reverse forelimb asymmetry are also potentiated when the compound is coadministered with an inactive dose of l-DOPA, suggesting that mGlu4 positive allosteric modulator may provide l-DOPA-sparing activity. [1]

The effects of VU0364770 on rat mGlu1 and mGlu5 are assessed by using calcium mobilization and measuring the glutamate concentration-response relationship in the presence and absence of 10 μM VU0364770. Using a double-addition protocol, VU0364770 is added to the cells, followed 2.5 min later by a full concentration-response of glutamate. Shifts of the concentration-response relationship are used to assess potential potentiator (left shift of more than 2-fold) or antagonist (right shift of more than 2-fold or depression of the maximum response by at least 75%) activity of VU0364770. Compounds are further assessed for mGlu5 antagonist activity by performing a full concentration-response curve, starting at 30 μM and serially diluted it by using 1:3 dilutions, in the presence of an EC80 concentration of glutamate[1].