Premise: Dopamine ( DA , contracted from 3,4-dihydroxyphenethylamine ) is an organic chemical of the catecholamine and phenethylamine families that plays several important roles in the brain and body . In the brain , dopamine functions as a neurotransmitter -- a chemical released by neurons ( nerve cells ) to send signals to other nerve cells .
Hypothesis: Dopamine is in the heart.
Label: NEUTRAL