Brain Mind Center

Neurotransmitters Catecholamines

Norepinephrine and dopamine are utilized in brain circuits which regulate all body functions, mood, emotions, and cognitive abilities. These transmitters are made from amino acids, supplied as proteins in foods or as free amino acids in formulas such as Alpha ENF. Phenylalanine and tyrosine are first converted to l-dopa, then dopamine, which can be converted to norepinephrine and epinephrine.

Norepinephrine is widely distributed in the brain and is the neurotransmitter in neurons that determines consciousness, sleep rhythms, attention, and vigilance. NE cell clusters within the brain's arousal complex (locus coeruleus) organize sleep patterns. In rats, painful, uncontrollable electrical shocks induce “depression” and are associated with early depletion of NE in the locus coeruleus.

Underproduction of NE may lead to depression. Some antidepressants, especially imipramine, selectively alter the synthesis of NE, but paradoxical experimental results tell us that therapeutic changes are not achieved by just increasing one transmitter but rather influencing the net arousal balance in the mesh of arousal circuits.

Imipramine, the grandmother of the family of tricyclic antidepressants, has at least a triple action on NE, acetylcholine, and histamine circuits. Imipramine's cousin, amitriptyline, works more on the serotonin neurons and also has marked anti-acetylcholine activity. Both drugs are also good antihistamines.

The substrates of NE, phenylalanine, tyrosine, and l-dopa are not powerful antidepressants, but they may have a contributing role in a well thought-out neurochemical recipe. Stimulants, including caffeine, cocaine and amphetamines act in a NE-increasing mode with temporary increase in psychic energy and a sense of well-being. They also influence the dopamine system.

Repeated use of these drugs leaves the over stimulated brain circuits in a state of confusion, with disturbances of psychic energy, thinking, feeling, and behaving. Withdrawal from these drugs is associated with other marked disturbances.

Amphetamines will induce agitated, paranoid, and violent states in susceptible people. As street drugs, amphetamines have major antisocial consequences. Antidepressants of the MAO-inhibitor group (parnate, nardil) increase norepinephrine levels but not serotonin.


Further reading: Neuroscience Notes, Intelligence and Learning, Language & Thinking

Persona Digital

Persona Digital Books is the publisher of The Human Brain, Neuroscience Notes, Intelligence & Learning and related books. Three books are available as print editions for mail delivery. All books are available as eBooks for download (PDF files).

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