The competitive NMDA antagonist CPP blocks MK-801-elicited popping behavior in mice.

In the current investigation, the ability of CPP (3-(2-carboxypiperazine-4-yl) propyl-1-phosphate) to elicit mouse popping behavior in a manner similar to that of MK-801 was studied. Unlike MK-801, CPP (3.2-32 mg/kg) did not elicit any popping. The data show that a reduction in NMDA-mediated neural transmission alone is not sufficient to elicit popping behavior in mice. Moreover, pretreatment of mice with CPP attenuated MK-801's ability to elicit popping. These results suggest that popping requires the channel to be in the "active", or open, configuration and that it depends on MK-801's access and binding to its unique site in the hydrophobic channel domain.