Parcel Select. Parcel Select is an economical choice for large or heavy packages and is the only USPS service that can be used for packages over 108 in girth. Cost is determined based on the distance, weight and dimensions of the mailpiece.
Definition of dopamine. : a monoamine C8H11NO2 that is a decarboxylated form of dopa and that occurs especially as a neurotransmitter in the brain.
The Biochemistry of Addiction. Dopamine plays an important role in the reward system. Dopamine is a natural chemical in the brain that sends signals to the limbic system. When introduced into the limbic system, drugs either mimic dopamine or cause an overproduction of it in the brain. The reason normal actions that activate the brain reward system (food, drinking, sex, music, etc.) donât reprogram the brain for addiction is because they produce normal levels of dopamine.