This is a randomized, double-blind, placebo-controlled, ascending multiple-dose study evaluating AMG 333 in healthy subjects and subjects with migraines. Eight healthy subjects will be enrolled in each of cohorts 1 through 5. Study subjects will be randomized such that 6 subjects will receive AMG 333 and 2 subjects will receive placebo (3:1 ratio) per cohort. Likewise, 8 migraine subjects will be enrolled in cohort 6 and randomized to receive AMG 333 or placebo (3:1 ratio). All subjects will be housed for 15 days then allowed to return home. Migraine subjects will self-administer the headache diary at least once daily during the screening and out-patient portions of the study, and site personnel will administer the headache diary during the in-house period of the study. Healthy subjects will not keep the headache diary during screening and will have the headache diary administered by site personnel at least once daily starting on day 1 through day 14, and will then self administer throughout their participation in the study.