CHEMISTRY OF THE BRAIN: MOLECULES, MOOD, AND MENTAL ILLNESS - Chemistry: Notable Research and Discoveries - page 97

nucleus accumbens. The report “Nucleus Accumbens D2/3 Receptors Pre-
dict Trait Impulsivity and Cocaine Reinforcement,” published in Science
in 2007, indicates that the physiological state of dopamine neurotransmis-
sion may be an important factor leading to substance abuse problems.
Dopamine and other brain chemicals profoundly influence the way
people think and feel. Variability in these chemicals, particularly in the
way they are regulated, affects a person's mental health, response to medi-
cation, propensity for or against danger, and other behaviors. A greater
understanding of brain chemistry will not only provide more insight into
what it means to be human, it will also lead to superior treatments and
preventative measures to some of the most serious problems plaguing
society.
ConCluSIon
Neurochemists continue to improve the methods they use to measure
and analyze chemicals of the brain. They have also developed techniques
to study how neurons transmit messages across synapses to other neu-
rons, and how these messages affect the recipients. Synaptic transmis-
sion is critical in brain function, and neurotransmitter imbalances have
been associated with disorders such as depression and schizophrenia
as well as drug abuse. Although the cause or causes of these conditions
are not necessarily as simple as too much or too little of a certain neu-
rotransmitter, chemicals such as dopamine and serotonin are undoubt-
edly involved. Neurotransmitters have been excellent starting points for
further, ongoing studies into these issues.
Some people wonder if researchers may one day develop procedures
to regulate neurotransmission artificially. Simple procedures that influ-
ence neurotransmission already exist—including drug abuse, in which
users alter their brain chemistry, albeit in an unintentional and unpro-
ductive fashion. Other substances such as naltrexone have been found
that counter the “high” of drugs of abuse. Naltrexone blocks transmission
of neurotransmitters known as opiates that are involved in mediating the
effect of morphine and its more potent chemical derivative, heroin. In
1984, the Food and Drug Administration (FDA), which regulates food
and drug safety in the United States, approved the use of naltrexone in
morphine and heroin addicts. (Naltrexone should not be confused with
naloxone, a drug used to counteract morphine and heroin overdoses.)
Since it impedes transmission, naltrexone helps to block the rewarding