View Full Version : Norepinephrine (NE), Dopamine (DA), Serotonin (ST)

03-05-13, 12:42 PM

Biogenic amines as neurotransmitters in CNS-

-Norepinephrine (NE), dopamine (DA), and serotonin (ST) belong to the group of biogenic monoamine neurotransmitters

that serve in the central neural pathways regulating affective states (moods, motivation, feelings) and in self-awareness, consciousness, and personality.

Drug effects of CNS established roles for NE, ST, & DA in affective behavior & mental disorders-

-Reserpine, a plant alkaloid known to reduce hypertension, acts by decreasing storage of synaptic vesicles and availability of NE in peripheral synapses .

Reserpine treatment for blood pressure also causes central "affective disorders" such as depression and loss of appetite and interest.

Reserpine has been used for centuries in India to relieve mania (abnormally elevated moods) in mental patients.

These observations implicate NE, ST, and DA in regulating mood and feeling (affective states).


Norepinephrine & serotonin pathways originate in the midbrain & project to the forebrain-

-Mapping studies using fluorescent staining techniques showed that the neurons releasing these amines make up nerve groups within the recticular formation.

The cell bodies are generally located in the brain stem and the fibers ascend to the forebrain, targeting a variety of structures.

There are two NE projections.

One originates in the locus ceruleus of the medulla and courses up along the medial forebrain bundle to innervate the cerebral cortex and limbic system.

NE fibers do not innervate the basal ganglia.

Another NE pathway forms the lateral group innervating the hypothalamus and basal forebrain.

The ST neurons originate mainly in the raphe nucleus and innervate many forbrain areas.

Recent research indicates that the locus ceruleus NE system is involved mostly in arousal and attention,

while the ST system regulates moods, motivation, pleasure, and well-being.

Mesocortical DA pathway is involved in behavior-

-The DA pathways also begin in the midbrain.

One pathway ends in the hypothalamus, another in the basal ganglia,

and a third--mesocortical (mesolimbic) pathway--ends mainly in the structures of the limbic system and the frontal lobes.

This mesolimbic pathway in particular serves in complex mental functions related to the frontal lobe and limbic system

(i.e., goal-directed behavior, self-awareness, thinking and planning, anxiety).

The PHYSIOLOGY Coloring Book, Kapit/Macey/Meisami, Biogenic Amines, Behavioral Functions & Mental Disorders, P110