4-3 Neurobiological Aspects of
Psychiatric Disorder
What are the two organizational systems of the CNS? - ANSWER-Hierarchical neuronal systems
Nonspecific, diffuse neuronal systems
Hierarchial Neuronal Systems - ANSWER-Sensory Perception, motor control
GABA, Glycine, Glutamate
Nonspecific, Diffuse Neuronal Systems - ANSWER-Monoamines, Ach
Cell bodies in discrete nuclei
Where is a neurotransmitter molecule synthesized? - ANSWER-Neuron
Where is the neurotransmitter molecule present and when is it released? - ANSWER-The molecule is
present in the presynaptic neuron and is released on depolarization in physiologically significant
amounts
What does an exogenous neurotransmitter do when given as a drug? - ANSWER-Mimics the effects of
the endogenous neurotransmitter
What happens in the synaptic cleft to a neurotransmitter? - ANSWER-A mechanism in the neurons of
the synaptic cleft acts to remove or deactivate the neurotransmitter
What are two types of ion channels? - ANSWER-Voltage gated
Ion gated
G-protein coupled receptor (GPCR) modulating gated ion channels two unique factors - ANSWER-
Membrane delimited
Diffusible
What controls the gating of a voltage gated channel? - ANSWER-Voltage sensor component of the
protein controls the gating
What controls the gating of ligand-gated channels? - ANSWER-Binding of NT to inotropic channel
receptor controls the gating of the channel
What happens when a GPCR is bound? - ANSWER-It activated a heterotrimeric G protein
What are the two ways metabotropic receptors can regulate ion channels? - ANSWER-The activated G
protein can interact directly to modulate an ion channel
The G protein can activate an an enzyme that generates a diffusible second messenger (cAMP) which
can interact with the ion channel or can activate a kinase that phosphorylates and modulates a
channel
Dopamine receptor subtypes and preferred agonists - ANSWER-D1- dihydrexidine
, D2- bromocriptine
D1-dihydrexidine mechanism - ANSWER-Increase cAMP
D2-bromocriptine mechanism - ANSWER-Decrease cAMP
3 modes of CNS communication - ANSWER-Ultra Fast
Fast, moderately sustained action
Slow, modulation
Ultra fast CNS communication - ANSWER-Amino acid neurotransmitters
-Senses (vision)
-Sustained effects (GABA, glutamate)
Fast, moderately sustained action CNS communication - ANSWER-Peptides
-enkephalins
Monamines
-Emotional tone and emotional lability
Slow, modulation CNS communication - ANSWER-Hormones
-Estrogens and androgens
GABA (amino acid neurotransmitter) - ANSWER-Predominant inhibitory neurotransmitter
Important in alcohol and anxiolytic drug effects -diazepam-type drugs
Important for anti-seizure medications
Inadequate levels of GABA can result in anxiety
GABAα Structure - ANSWER-7 subunits (α,β,γ,δ,ε,η,θ)
Some subunits have multiple subtypes (α,β,γ)
5 subunits form the receptor complex
-Approx. 100+ variants of GABAα receptor possible
-Several exist in the mammalian CNS
The most common GABAα structure - ANSWER-2α, 2β, 1γ
Where does the GABA appear to interact on the GABAα receptor? - ANSWER-At two sites between
the α and β subunits
What happens when GABA binds to the GABAα receptor? - ANSWER-Chloride channels open and
result in membrane hyperpolarization
What are some of the allosteric sites on the GABAα receptor? - ANSWER-Benzodiazepines, hypnotic
drugs (zolpidem), and flumazenil
Benzodiazepines and zolpidem facilitate the flow of chloride while flumazenil inhibits the flow of
chloride
What does increased Cl conductance do to neural firing?
Psychiatric Disorder
What are the two organizational systems of the CNS? - ANSWER-Hierarchical neuronal systems
Nonspecific, diffuse neuronal systems
Hierarchial Neuronal Systems - ANSWER-Sensory Perception, motor control
GABA, Glycine, Glutamate
Nonspecific, Diffuse Neuronal Systems - ANSWER-Monoamines, Ach
Cell bodies in discrete nuclei
Where is a neurotransmitter molecule synthesized? - ANSWER-Neuron
Where is the neurotransmitter molecule present and when is it released? - ANSWER-The molecule is
present in the presynaptic neuron and is released on depolarization in physiologically significant
amounts
What does an exogenous neurotransmitter do when given as a drug? - ANSWER-Mimics the effects of
the endogenous neurotransmitter
What happens in the synaptic cleft to a neurotransmitter? - ANSWER-A mechanism in the neurons of
the synaptic cleft acts to remove or deactivate the neurotransmitter
What are two types of ion channels? - ANSWER-Voltage gated
Ion gated
G-protein coupled receptor (GPCR) modulating gated ion channels two unique factors - ANSWER-
Membrane delimited
Diffusible
What controls the gating of a voltage gated channel? - ANSWER-Voltage sensor component of the
protein controls the gating
What controls the gating of ligand-gated channels? - ANSWER-Binding of NT to inotropic channel
receptor controls the gating of the channel
What happens when a GPCR is bound? - ANSWER-It activated a heterotrimeric G protein
What are the two ways metabotropic receptors can regulate ion channels? - ANSWER-The activated G
protein can interact directly to modulate an ion channel
The G protein can activate an an enzyme that generates a diffusible second messenger (cAMP) which
can interact with the ion channel or can activate a kinase that phosphorylates and modulates a
channel
Dopamine receptor subtypes and preferred agonists - ANSWER-D1- dihydrexidine
, D2- bromocriptine
D1-dihydrexidine mechanism - ANSWER-Increase cAMP
D2-bromocriptine mechanism - ANSWER-Decrease cAMP
3 modes of CNS communication - ANSWER-Ultra Fast
Fast, moderately sustained action
Slow, modulation
Ultra fast CNS communication - ANSWER-Amino acid neurotransmitters
-Senses (vision)
-Sustained effects (GABA, glutamate)
Fast, moderately sustained action CNS communication - ANSWER-Peptides
-enkephalins
Monamines
-Emotional tone and emotional lability
Slow, modulation CNS communication - ANSWER-Hormones
-Estrogens and androgens
GABA (amino acid neurotransmitter) - ANSWER-Predominant inhibitory neurotransmitter
Important in alcohol and anxiolytic drug effects -diazepam-type drugs
Important for anti-seizure medications
Inadequate levels of GABA can result in anxiety
GABAα Structure - ANSWER-7 subunits (α,β,γ,δ,ε,η,θ)
Some subunits have multiple subtypes (α,β,γ)
5 subunits form the receptor complex
-Approx. 100+ variants of GABAα receptor possible
-Several exist in the mammalian CNS
The most common GABAα structure - ANSWER-2α, 2β, 1γ
Where does the GABA appear to interact on the GABAα receptor? - ANSWER-At two sites between
the α and β subunits
What happens when GABA binds to the GABAα receptor? - ANSWER-Chloride channels open and
result in membrane hyperpolarization
What are some of the allosteric sites on the GABAα receptor? - ANSWER-Benzodiazepines, hypnotic
drugs (zolpidem), and flumazenil
Benzodiazepines and zolpidem facilitate the flow of chloride while flumazenil inhibits the flow of
chloride
What does increased Cl conductance do to neural firing?
