Serotonin (INITIATE SLEEP) – Raphe Nuclei, SSRIs antidepressants
Behavioral medicine and SAND
•The transmitter of a discrete group of neurons.
•Involved in the therapeutic mechanism of action of antidepressants
•Has inhibitory influence; linked to impulse control.
• Has role in regulation of mood, sleep, sexual activity, aggression,
anxiety, motor activity, cognitive function, appetite, circadian rhythms,
neuroendocrine function, and body temperature
• Involved in various neuropsychiatric disorders, e.g., depression, mania,
impulsive aggression, schizophrenia, anxiety, obsessive-compulsive
disorder, autism, Alzheimer disease, chronic pain, anorexia, bulimia,
•The exact role of ACh in the brain unclear
•Cholinergic neurons concentrated in the RAS and basal forebrain
•Significant role in Alzheimer disease.
•Associated with erections in males.
•Associated with REM stage of sleep.
•Ach increases relative to Norepi. In depression.
•In the corpus striatum, ACh circuits are in equilibrium with dopamine
•Implicated in altering attention, perception, and mood
•Implicated in monoamine hypothesis of affective disorders:
– Depletion of NE leads to depression
– Excess of NE (and serotonin) leads to mania
Three pathways of known psychiatric importance:
a. Nigrostriatal pathway in substantia nigra (movement disorders)
– Neuroleptics or destruction of dopaminergic cells and Parkinson disease.
b. Meso-limbic-cortico pathway (psychosis)
-Postsynaptic dopamine blockade and antipsychotic symptoms
-Neuroleptic medications reduce the hallucinations, delusions.
-Dopamine levels are in depression and higher in mania.
-Amphetamines aggravating psychotic symptoms.
c. Nucleus accumbens (NAC) pathway
-The addiction pathway