Hello!! Your answer would be serotonin. Serotonin is a compound that is present in blood platelets that constricts the blood vessels. Consequently, it acts like a neurotransmitter. It is also a brain chemical that sends messages to other cells. In children who are diagnosed with SIDS, they have low levels of serotonin which helps regulate breathing, heart rates, and sleeping. I hope this helped!! Have a great night.
