CNS Neurotransmitters (5) Flashcards
What is the precursor for acetylcholine?
acetyl coA + choline
What type of receptors does acetylcholine have?
ionotropic and metabotropic
What is the function of acetylcholine in the peripheral nervous system?
It is a neurotransmitter at NMJs
What is the precursor for glutamate?
Glutamine
Can glutamate cross the blood brain barrier?
no, but glutamine can
What type of receptors does glutamate have?
Ionotropic and metabotropic
What is the function of glutamate?
It is a major excitatory transmitter in the brain
What is the precursor of GABA?
Glutamic acid
What type of receptors does GABA bind to?
Ionotropic and metabotropic
Which of these neurotransmitters is removed from the synaptic cleft by an enzyme and NOT by reuptake into terminal and glia?
- Ach
- Glu
- GABA
- Gly
- Dopamine
- NE
- Serotonin
ACh - acetylcholinesterase
What is the function of GABA?
Major inhibitory transmitter in brain
What is the precursor of glycine?
Serine
What type of receptors does glycine bind to?
Ionotropic
What is the function of glycine?
Major inhibitory transmitter in spinal cord
What is the precursor for dopamine?
Tyrosine
What type of neurotransmitters are dopamine and NE?
Catecholamines
What type of receptors does dopamine bind to?
Metabotropic
What is the function of dopamine?
Coordination of body movements
motivation, reward, reinforcement
emotional behavior
What is the precursor for NE?
Tyrosine
What type of receptors does NE bind to?
Metabotropic
What is the function of NE in the CNS and PNS?
CNS: sleep, wakefulness, attention, feeding behavior
PNS: sympathetic motor system
What is the precursor for serotonin?
Tryptophan
What type of receptors does serotonin bind to ?
Metabotropic and ionotropic (minor)
What is the function of serotonin?
Regulation of sleep, eating
wakefulness and arousal
What is myasthenia gravis?
Autoimmune disorder in which antibodies are produced to nicotinic ACh receptors
What are the precursors for neuropeptides?
Amino acids in the ER
What type of receptors do neuropeptides bind to?
metabotropic
How are neuropeptides removed from synaptic cleft?
Peptidases
What is the function of neuropeptides?
Modulate emotions
perception of pain
response to stress
Which type of neurotransmitters can respond to increased demand: small molecule or neuropeptides?
Small molecules since they are made in the nerve terminal
What does sarin gas do?
It blocks acetylcholinesterase causing spastic paralysis due to continued depolarization
What are atropine and scopolamine and what are they used to treat for?
both are antagonists of Ach
atropine - pupil dilation
scopolamine - motion sickness
With which neurotransmitter can exictotoxicity occur and what is this?
Glutamate
- high extracellular concentrations toxic to neurons
- though to occur in strokes
- O2 deprivation slows reuptake
Name three ionotropic receptors that glutamate can bind to?
NDMA, AMPA, Kainate
What is special about the NMDA receptor?
ca2+ can pass in addition to Na+
ion flow is voltage dependent - mg2+ binding
depolarization needs to occur for Mg2+ to move
What can result from decreased GABA function?
Epilepsy
What are the symptoms of the neonatal disease in which there is excess synaptic glycine due to defects in the glycine transporter?
lethargy and mental retardation
What is benzodazepines?
valium is an example
- used as tranquilizers
- agonists of GABA
What is strynchine?
Glycine receptor antagonist - blocks
overreactivity in spinal cord and brainstem –> seizures
used to poison rodents
What type of ions do GABA and Glycine receptors permit?
Cl-
What are barbituates?
GABA receptor agonists used as anesthetics to treat epilepsy
What are GABA reuptake inhibitors used for?
Treat anxiety and panic disorders
How does the expression of biogenic amines compare with the expression of glutamate and GABA?
GABA and glutamate are ubiquitously synthesized
their receptors are widely expressed
Biogenic amines are limited in synthesis
their receptors are broadly expressed
allows for controlled specific signals
Where is 80% of dopamine found in the brain?
In the corpus striatum
caudate and putamen
What is involved in parkinson’s disease? How can it be treated?
the neurons which project from substantia nigra to striatum degenerate and dopamine is not sufficiently released
can be treated with dopamine precursor - LDOPA
What are antagonists of dopamine in the medulla used to treat?
anti-emetics used to treat nausea and vomiting
What is the effect of cocaine on neurotransmitter transporters?
It inhibits dopamine transporters leading to a net increase in release of dopamine
-addiction
What is the effect of amphetamines on neurotransmitter transporters?
They inhibit both dopamine and NE transporters leading to a net increase of both neurotransmitters
Where are most the neurons that use serotonin as a neurotransmitter located?
In raphe nuclei in the upper brainstem and project widely to the forebrain
Name two types of anti-anxiety drugs
- MAO inhibitors - block breakdown of biogenic amines
2. inhibitors of serotonin receptors
What do anti-psychotic drugs block?
Dopamine receptors
Name the 3 classes of anti-depressants
- MAO inhibitors
- tricyclic - block reuptake of NE and serotonin
- serotonin reuptake inhibitors - prozac
