artiCLe | NeurosCIeNCe | Amino acids
Glutamate Aspartate Glycine GABA
Catecholamines Monoamines Indolamines Soluble gases Acetylcholine one can say that at the level of the skin, the presence
of many neurotransmitters (e.g. ACh, GABA, serotonin, dopamine) has been revealed and their functions are known to be much more specific. The similarities between the brain’s and the skin’s effects are interesting and can be related to embryogenesis. This is a common denominator between the two organs, where we find the same neurotransmitters with the same functions. In the brain, the main neurotransmitters have roles
which are now beginning to become clear (Figure 2). dopamine is linked to reward and energy, much like a booster for cells. This neurotransmitter plays a significant role in addiction, and in processes controlling movements, emotions, and pain. Monoamine oxidase (MAo) is a vital enzyme in the regulation of dopamine, like catechol-o-methyltransferase (CoMT) 1
. Pigmented
neurons with neuromelanin are particularly sensitive to neurodegeneration in the course of Parkinson’s disease2
. ACh and dopamine have potent interactions
within the striatum — at multiple levels — that include presynaptic regulation of neurotransmitter release and postsynaptic effects in target cells (including ACh neurons)3
. ACh is associated with Alzheimer’s disease,
memory, and neuronal speed. Peripheral ACh is related to muscle function and is a significant actor in the autonomic nervous system. serotonin is a mood enhancer, often referred to as a
‘day guard’ (as opposed to the night guard, melatonin). some repair processes and mitosis control depend on serotonin4
. The chemical proximity of serotonin and
melatonin proves the strong correlation between them and their successive impacts. GABA is the only inhibitory neurotransmitter, but is
also a modulator, often creating a balance between cells in order to avoid excess, and to protect.
Nitric oxide Nitric oxide (No) is a potent vasodilator and plays a key role in establishing both whole-body and regional
54 ❚ July 2011 |
prime-journal.com
attention motivation Pleasure reward
sleep mood
obsessions Compulsons
Dopamine Adrenaline
Noradrenaline Serotonin
Nitric oxide Carbon monoxide Acetylcholine
Figure 1 Classes of neurotransmitters
‘vascular tone’. In this context, skeletal muscle and the skin have the remarkable capacity to increase blood flow by 50–100-fold, and this increase is caused almost exclusively by local vasodilation5
. It also plays an
important role in blood pressure regulation studies have revealed the cardio-protective function . If uVBs are responsible for the production of
of No6
vitamin d, uVAs create the production of No in the skin, and represent a notable source that has a rapid cardiovascular vasodilator effect. The lifespan of No is approximately one nanosecond
because it can fast become dangerous for cellular organelles (No, after uVB impact, influences oNoo¯ (peroxynitrite)-induced apoptosis). Its metabolites have long lifespans, which compensate for this, such as nitrites and s-nitrosothiols, which are found in the circulatory system. The epidermis is rich in sulfhydryls, which form No at
a concentration much higher than that of plasma. It seems that uVAs can increase nitrates in the blood by 40%. Furthermore, vitamin d via uVB also stimulates the production of No just like uVAs. What is particularly intriguing is that sunlight — via the production of melatonin — regulates No activity, thus creating a subtle balance to its potentially dangerous short-term activity. All of the skin’s cells produce No either naturally or
via the stimulation of inflammatory cytokines. uVAs facilitate the transfer of No from the epidermis to the circulatory system (340–360 nm and 453 nm) and 40% are found in plasma. Nutrition can work with sunlight to encourage this production7
. however, it is worth noting
that glutathione, the body’s main antioxidant, is linked to No within a protective chain of thiol proteins8
, where it
Figure 2 Functions of the body’s main neurotransmitters
acts as the immediate blocker of No. No has a key role in the occurrence and maintenance
t
alertness energy stress
arousal
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