A Study of TAK-951 in Healthy Adults

This is a study of TAK-951 for people with symptoms of nausea and vomiting. The main aims of this study in healthy adults are as follows: * To check for side effects from TAK-951 when given at a slow and fast infusion rate. * To learn how much TAK-951 participants can receive without getting side effects from it. * To check how much TAK-951 stays in the blood over time to work out the best dose. Participants will receive a single infusion of either TAK-951 or placebo. In this study, a placebo looks like TAK-951 but does not have any medicine in it. Participants will receive either a low dose or high dose of TAK-951. The infusion will take from 1-3 hours. Participants will stay in the study clinic for about 4 days to receive the study medicine (TAK-951 or placebo) and check for side effects. They will have follow-up visits at the clinic about 2 weeks and 4 weeks after treatment.