Nervous System Health Flashcards
5 factors affecting nervous system health
- lifestyle
- Nerve cell structure and function
- Hormonal and immune health
- Energy delivery
- GIT health
Definition of the Gut-Brain axis
Bidirectional communication between the CNS and the enteric NS
% of sensory nerve fibres in the vagus nerve
% of motor nerves
- afferent (sensory): 80%
- efferent (motor): 20%
4 ways gut microbiota interact with the Gut-Brain axis
- Microbes modulate neurotransmitter production
- Production of bacterial metabolites: SCFAs that support mucosal serotonin release and influence memory/learning
- Modulate afferent sensory nerves
- BDNF function can be modulated by microbiota
Microbiome species that has been shown to enhance neuron excitability, modulate gut motility and pain perception
L. reuteri
how does gut barrier function affect mental health?
- Gut dysbiosis can cause damage to the mucosal layer
- This causesintestinal permeability (via local immune reactions)
- This leads to metabolic endotoxemia
- This can lead to neuroinflammation and depression
3 physiological stressors/drivers that affect NS function
- Inflammation
- Oxidative stress
- Toxic load
2 neurotrophic factors and 3 factors that decrease the expression of these
- BDNF
- NGF
- Physical and psychological stress
- Ageing
- Lack of physical activity
Definition of a neurotransmitter
chemical messengers released from a pre-synaptic terminal, causing an excitatory or inhibitory effect on the post synaptic cell.
6 factors that contribute to NT imbalances
- Inadequate nutrition
- High stress
- Toxicity
- Genetic SNPs
- Poor digestive health
- Drug use
Methylation produced co-factor for serotonin and dopamine production
Methylation produced co-factor for melatonin and adrenaline production
Methyl folate for biopterin (serotonin and dopamine
SAMe (methyl folate and B12) - melatonin and adrenaline
NT breakdown - list 2 key enzymes and the NTs they help to break down
- MAO: serotonin, adrenaline, noradrenaline, dopamine
- COMT: adrenaline, noradrenaline, dopamine (uses a methyl group from SAMe)
Which NTs synthesised in the gut can pass the blood brain barrier
Which cannot
GABA can pass the BBB
Serotonin and Dopamine can’t
2 ways serotonin is produced in the GUT
% produced in the gut
- produced by enterochromaffin cells
- produced by bacteria
95%
Can serotonin cross the blood brain barrier? If not, how can serotonin be made in the brain
Serotonin can not cross the BBB
Tryptophan and 5HTP can
6 functions of serotonin
- Motility (GI signalling)
- Mucosal secretions
- Mood
- Appetite
- Sleep (melotonin)
- Blood clotting
Organic acid testing (OAT) for serotonin - what metabolite can you test for?
5-HIAA - a serotonin metabolite that can indicate serotonin levels
Serotonin co-factors
- Zinc
- Iron
- Magnesium
- Folate
- B6
Low serotonin: causes/risk factors
- Nutritional insufficiencies
- Chronic stress
- GI dysbiosis
- Lack of sunshine
- Caffeine
- Alcohol use
- sedentary lifestyle
How does statin use affect serotonin
cholesterol depletion impaires serotonin receptor function
What is the enzyme that converts tryptophan to 5HTP?
What is the enzyme that converts 5HTP to 5HT?
TPH
Aromatic Acid Decarboxylase
What are the co-factors for conversion of serotonin to melatonin (2 stages)
- 5HT to N-acetylserotonin: B5 (acetyl coA)
- N-acetylserotonin to melatonin: SAMe (MTHF and B12)
Why does chronic stress reduce levels of serotonin?
High cortisol downregulates the uptake of serotonin via 5HT receptors
How does caffeine affect serotonin levels?
How does alcohol affect serotonin levels?
- Caffeine inhibits the TPH enzyme (converion of tryptophan to 5HTP)
- Alcohol lowers serotonin
