EXAM 3: Neurochemistry
Increased release induces epilepsy
aspartate & glutamate
Classified as an excitatory neurotransmitter
aspartate & glutamate
Classified as an inhibitory neurotransmitter
GABA & glycine
Classified as a peptide neurotransmitter
endorphins & substance P
Classified as a catecholamine (NOT acetylcholine!)
dopamine, epinephrine & norepinephrine
Made primarily in the brainstem substantial nigra
dopamine
Made by motor neurons
acetylcholine
Decreased release results in depression
norepinephrine & serotonin
Activation of receptor causes sedation
GABA & glycine
Reduced activity cause muscle weakness or paralysis
acetycholine
Transmits pain sensation from the periphery
substance P
Increased activity involved in schizophrenia
dopamine
Increased activity produced mania
norepinephrine
Plays a role in attention/alertness and learning/memory
acetylcholine
Valium and barbiturates bind to this receptor
GABA
Neurotransmitter is degraded in synaptic cleft
acetylcholine
Death of substantial nigra neurons that make dopamine
Parkinson’s disease
Death of forebrain neurons that make acetylcholine
Alzheimer’s disease
Death of motor neurons due to glutamate neurotoxicity
ALS/ Lou Gehrig’s
Autoimmune destruction of acetylcholine receptors
myasthenia gravis
Loss of function in the enzyme acetylcholinesterase would result in?
inability to destroy and remove acetylcholine from the synaptic cleft
When a neurotransmitter like GABA is acting in an inhibitory manner what is the likely result of the GABA acting on the post-synaptic cell?
hyperpolorization of the post-synaptic cell membrane
-because it causes entry of chloride and exit of potassium
-because it causes entry of chloride and exit of potassium
Which of the following neurotransmitters inhibits pain and is mimicked by morphine, heroin and methadone?
endorphins
Why can the effect of acetylcholine be stimulating or inhibiting?
different post-synaptic cells will have different receptors
Post-synaptic response due to excitatory neurotransmitter binding
increased the probability of neurotransmitter release by causing an EPSP due to sodium entry into the post-synaptic neuron
Post-synaptic response due to inhibitory neurotransmitter binding
decreases the probability of neurotrasmitter release by causing an IPSP due to calcium entry or potassium exit through the post-synaptic neuron
Ionotropic receptors
allow ions to directly enter the post-synaptic receptor
Second messenger-mediated receptors
indirectly cause ion entry through a second receptor
Why is it difficult to alter neurotransmitter levels without having significant side effects?
-Adding a neurotransmitter will activate all receptors
-drugs that block a specific neurotransmitter receptor subtype leads all brain regions with that receptor subtype will be affected
-example: Parkinson’s and Schizophrenia
-drugs that block a specific neurotransmitter receptor subtype leads all brain regions with that receptor subtype will be affected
-example: Parkinson’s and Schizophrenia
Why is it so difficult to diagnose depression?
-symptoms differ from person to person
-stigma
-asking the right questions
-stigma
-asking the right questions
Why is it so difficult to treat depression?
-lower levels of serotonin and noradrenalin as well as dopamine contribute
-takes time for drugs to work
-people think they are better and suddenly stops taking meds
-takes time for drugs to work
-people think they are better and suddenly stops taking meds