Neurochemical Circuitry Flashcards
What are the functions of nitric oxide?
- retrograde signaling
- increase cGMP -> regulates Ca homeostasis
- rapid signaling
How is nitric oxide synthesized?
from arginine via NO synthase on demand
How is carbon monoxide synthesized?
from heme via heme oxygenase
What characteristics do nitric oxide and carbon monoxide share?
- NOT stored in vesicles
- released via diffusion
- NO receptors
What are the functions of carbon monoxide?
- retrograde signaling
- regulates cGMP -> mediates smooth muscle contraction
- rapid signaling
High affinity receptors are apart of what family?
Trk family
Low affinity receptors are apart of what family?
BDNF
Where are BDNF and NGF synthesized and released from?
soma and dendrites
Where are BDNF and NGF synthesized and released from after depolarization?
soma, dendrites, nerve terminals
What are the effects of BDNF?
- neurogenesis
- excitability
- brain connectivity
What is the effect of too much BDNF?
affects plasticity and may affect learning
What is the effect of too little BDNF?
affects plasticity and linked to increased depressive episode
How is Ach synthesized?
choline + acetyl CoA by enzyme choline acetyltransferase
How is the action terminated in Ach?
hydrolysis by ACHE
What is the effect of too much ACh?
muscle contractions (ex: black widow venom)
What is the effect of too little ACh?
paralysis
What are the cholinergic circuits?
- basal forebrain neurons: degenerate in Alzheimer’s
- brainstem neurons: induces REM
How is serotonin synthesized?
from tryptophan by enzyme tryptophan hydroxylase
How is the action temrinated in serotonin?
- reuptake into presynaptic terminal
- catabolized by MAO-A
What are the indicated effects of serotonin?
- mood control
- homeostasis
- appetite & digestion
What is the effect of too much serotonin?
serotonin syndrome:
* confusion
* twitching/trembling
* dialted pupils
* shivering/goosebumps
* headache
* sweating/diarrhea
* irregular/fast heart beat
What is the effect of too little serotonin?
schizophrenia: depression, sleep changes
What are serotonergic circuits?
- caudal raphe nucleus
- rostral raphe nucleus
How is dopamine synthesized?
from tyrosine by enzyme tyrosine hydroxylase
How is the action terminated in dopamine?
- reuptake into pre-post synaptic terminal
What are the indicated effects?
- modulating movement
- inhibition of unwanted movement
What are the effects of too much dopamine?
schizophrenia
What are the effects of too little?
parkinson’s disease
What are the dopaminergic circuits?
- ventral tegmental area
- substantia nigra
What is the ventral tegmental area?
- important for goal oriented/reward behaviors
- actviated by drugs of abuse
What is substantia nigra?
- degenerate Parkinson’s disease
- control posture and movement
What is the key factor in liking?
serotonin -> mood stabilizer, wellbeing, happiness
What is the key factor in wanting?
dopamine -> motivational role in brain’s reward system
What is norepinephrine synthesized by?
dopamine -> tyrosine by enzyme tyrosine hydroxylase
How is dopamine transported into vesicle ?
VMAT2
How does dopamine turn into norepinephrine?
beta-hydroxylation
How is action terminated in norepinephrine?
- reuptake into pre-synaptic terminal
- catabolized by MAO-A and COMT
What are the indicated effects of norepinephrine?
alertness/attention
What is the effect of too much norepinephrine?
icnreased blood pressure, anxiety, sweating, headaches
What is the effct of too little norepinephrine?
lethargy, lock of focus, depression
What is the noradrenergic circuit?
locus coeruleus
How is glutamate synthesized?
from glutamine by enzyme glutaminase
How is glutamate transported into the vesicle?
VGLUT
How is the action temrinated in glutamate?
excitatory amino acid transproter
Which 2 circuits are widespread?
glutaminergic and GABA
What are the indicated effects of glutamate?
- main excitatory neurotransmitter
- role in synaptic plasticity, learning, and memory
- role in seizures
What is the effect of too much glutamate?
excitotoxicity and seizures
What is the effect of too little glutamate?
psychosis, coma, and death
How is GABA synthesized?
dopamine -> glutamate by enzyme glutamic acid decarboxylase
How is the action terminated in GABA?
GABA transporter
What is the indicated effects of GABA?
main inhibitory neurotransmitter
What is the effect of too much GABA?
over-sedation, over-relaxing of muscle including the heart and respiration
What is the effect of too little GABA?
anxiety, seizures
What is an agonist of GABA receptors?
baclofen
What is an antagonist of glutamate?
ketamine
