3 Flashcards
Serotonin (5-hydroxytryptamine; 5-HT)
• One of the biogenic amines derived from
tryptophan
Serotonin (5-hydroxytryptamine; 5-HT)
Broadly distributed in the brain. Its depletion in brain →
depression
Serotonin (5-hydroxytryptamine; 5-HT)
functions to regulate :
- Appetite,
- Sleeping, dreaming,
- Memory and learning,
- Temperature,
- Mood & emotional behavior,
- Biological clock.
- Muscle contraction,
- Functions of the CVS and endocrine systems.
Serotonin & Depression:
Anti-depressant drugs →
→ ↑ serotonin levels at the synapse by
blocking the reuptake of serotonin into the presynaptic neurons.
serious side-effects.
• If depression is mild, it can be managed by ↑ serotonin levels with
vigorous exercise
• A diet ↓ in omega-3 FAs → lower serotonin levels in brain→ depression.
• Complex CHO can → ↑ tryptophan in brain → calming effect.
• Vitamin C is also required for conversion of tryptophan → serotonin.
• Dietary serotonin as in banana has no effect…Why???
Purine Derivatives as Neurotransmitters
They are all derived from adenine-containing nucleotides or nucleosides
(ATP, ADP, AMP & adenosine).
ATP acts as a neurotransmitter in ……,……….
ATP regulates the
ATP acts as a neurotransmitter in both peripheral & CNS.
ATP regulates the release of transmitters from their synapse of origin.
ATP is released as an excitatory co-transmitter with norepinephrine from postganglionic sympathetic nerves, with acetylcholine from postganglionic parasympathetic nerves and from sensory, enteric and central neurons.
largest group of neurotransmitters.
NEUROPEPTIDES
NEUROPEPTIDES Many of them are “co-released” along with a small-molecule transmitter, but in some cases a peptide is the primary transmitter at
a synapse.
Many of the neuropeptides have a …………… residue at the N-terminus which is cyclized to form pyro-glutamate, while the C-terminus is often
an ……….
This provides better protection against
glutamate
acid amide (–NH 2).
This provides better protection against breakdown by peptidases.
Substance P & Capsaicin
released from the terminals of specific sensory neurons , found in the
released from the terminals of specific sensory neurons , found in the brain & spinal cord , and is associated with inflammatory processes & pain.
It’s responsible for transmission of pain from certain sensory neurons to CNS
Capsaicin (made from chili peppers) was found to ……. substance P levels at local nerve endings & ………..
↓ relieve pain.
Substance P & its endogenous receptor …………….
Substance P & its endogenous receptor neurokinin-1 receptor (NK1R) are
widely distributed in brain & are found in brain regions that regulate
emotion.
The …..amino acid sequence of substance P
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Neuropeptides Belong To Multigene Family
Neuropeptides Belong To Multigene Family
1. Pro-opio-melanocortin: contains β-endorphin.
2. Pro-enkephalin A: Contains Met- & Leu-enkephalins.
3. Prodynorphin: dynorphin.
Endorphins and encephalins are the body’s natural
painkillers
Encephalins block pain signals in spinal cord. Endorphins are thought to block pain principally at the brain stem.
The β-endorphin molecules are produced by the body as portions of larger
The β-endorphin molecules are produced by the body as portions of
larger pro-opio-melano-cortin (POMC) molecules, that expresses in the pituitary gland, then they are cut by enzymes into active subunits.
β-endorphin molecules cause
β-endorphin molecules cause pain relieve or produce pleasure feelings.
They are called the happiness hormones.
Pro-enkephalin A:
Met-enkephalin and leu-enkephalin are
composed of 5 amino acids joined by
peptide bonds.
They differ only in the amino acid present at
the C-terminal end.
Ways to Increase Endorphins in Your Body:
profound relaxation in a float tank triggers the production of endorphins .
Acupuncture needles into specific body points triggers production of endorphins.
A placental tissue of fetal origin (syncytiotrophoblast), excretes β- endorphins into the maternal blood system from 3rd month of
pregnancy.
exercise regularly have higher than usual amounts of β–endorphin in their bloodstream; as their levels ↑ during exercise, pleasure feelings.
