Inclusion Criteria:  Agree to effective method of birth control If female, negative pregnancy test at screening and Day -1 Nonsmoking at least 2 years BMI 18-30 Supine pulse rate 30-100  Exclusion Criteria:  Known hypersensitivity to NMDA receptor drugs clinically significant disease in any body system QTcF > 430 ms in males, >450 ms in females positive test for hepatitis B or C abnormal liver function tests on Day -1 History of alcohol or other substance abuse during the previous 5 years Positive drug screen at screening or Day -1 Taken any medication within the past 14 days