What are chemical messengers or neurotransmitters?
Chemical Messengers
• Neurotransmitter
• Serotonin
• Serotonin receptors
A neurotransmitter is a brain chemical that relays messages between brain cells and affects emotions, behavior, thoughts and regulates moods. Serotonin, norepinephrine and dopamine are just a few of the neurotransmitters present in the body.
Serotonin exerts its function by binding to receptors, then initiates a series of biochemical reactions finally leading to its physiological functions or behaviors. Serotonin receptors are proteins located on the surface of cells. The serotonin receptor works specifically for serotonin. When it binds to a receptor the signal is amplified inside the cell to begin transcription, enzyme activation, protein synthesis or the release of neuroactive agents. There are many different types of serotonin receptors which have different functions, and there are many different drugs which can increase or decrease the receptor’s function.
How does serotonin affect depression?
Physiological functions of serotonin:
– Hormone secretion
– Eating and body weight
– stereotypic behaviors
– Aggression
– Sexual behavior
– Pain sensitivity
– Anxiety
– Mental depression
– Learning and memory
– Circadian rhythms
– Sleep-wake cycles
– Temperature regulation
– Drug abuse
– Platelet aggregation
– Smooth muscle contraction
Serotonin levels in the brain
• What different levels of serotonin produce
• Re-uptake inhibitors
• MAO inhibitors
MAO A Gene Promoter Region
• What is it?
• Transcription factors
• CIS-elements
• Repressors
• Activators
What are the functions of MAO A and B?
MAO A and MAO B degrade neurotransmitters in the body so that they are in the optimum concentration. This video shows the interaction between inhibitors or serotonin and MAO active sites —amino acids and cofactors (yellow colored) involved in the substrate and enzyme binding. As it rotates, the inhibitors become serotonin (the little black balls).
3-D Model by J. Ma and A. Ito (2004)