Ch.5 Cont, Neurotransmitter Details

Question 1

Small molecule neurotransmitter characteristics

Answer 1

1. class of quick acting neurotransmitters: quick acting bc they are created IN the terminal and don’t require transportation to termiknal from elsewhere
2. Synethesized from dietary nutrients and packaged for use in axon terminals
3. Once released, they are quickly replaced at the presynaptic membrane

Question 2

List of amines and characteristics

Answer 2

made from amino acid precursors; HAVE a functional NH group
Includes: DA, NE/NA, EP/adrenaline, 5-HT

Question 3

Amino acid neurotransmitters and charachteristics

Answer 3

glutamate (Glu)
GABA

Question 4

What are the three major activating systems and what do they do?

Answer 4

neural pathways that coordinate brain activity through a single neurotransmitter (large scale brain pathways)
they synchronize brain activity across widespread regions
includes the cholinergic system, dopaminergic system, and sertonerig system: ALL SMALL MOLECULE NEUROTRANSMITTERS

Question 5

ACh: where does it work, how does it work, and what does it do?

Answer 5

Works primarily at the neuromuscular junction (including heart), which is an axomuscular synapse (pre is a motor neuron, post is a muscle fiber)
At heart: inhibitory
in somatic NS: excitatory ONLY
PROCESS:
1. ACh is synthesized in TERMINAL
2. ACh binds to receptor site (ligand)and releases its neurotransmitter WHICH —
3.. Opens the ion channel (a transmitter activated channel)
4. Na+ influxes into the cell
5. K+ effluxes out of the cell =NET DEPOLARIZATIOn/becoming more positive

Question 6

Anatomy of the neuromuscular junction

Answer 6

presynaptic=motor neuiron
End plate= post synaptic compartment

Question 7

Cholinergic system: neurotransmitter it uses, functions, regions of the brain it uses

Answer 7

1. Acetlycholine
2. Waking, memory, attention: keeping cortex activated. Death of cholinergic neurons and decreased ACh in the neocortex = related to Alzheimer disease
3. Basal forebrain nuclei (source of neurotransmitter) projects ACh through the neocortex, hippocampus, and amygdala

Question 8

DA

Answer 8

-synthesized from amino acid precursors (TYROSINE: sources are hard cheeses and bananas in the diet)
-Involved in coordinating movement, attention, learning, motivation, and reward processing
brain regions: basal ganglia to the striatum (putamen and caudate nucleus)

Question 9

How is DA implicated in Parkinson’s disease?

Answer 9

degeneration of the substantia nigra (midbrain), which is a small midbrain nucleus
Symptoms appear when DA levels have been reduced to less than 10% of normal levels in the basal ganglia bc neurons in the substantia nigra are dying
Basal ganglia to the striatum, which is involved in fluidity of movement: leads to tremors, rigidity, postural instability, slowness
Dyskinesia: parkinsons, involuntary erratic movements

Question 10

DA in the dopaminergic system

Answer 10

CNS, “MOVEMENT PATHWAY”
nigrostriatal pathways
active in maintaining normal motor behavior, loss = muscle rigidity and dyskinesia in parkinsons disease
Substantia nigra—striatum

Question 11

VS. DA in the mesolimbic pathways

Answer 11

REWARD PATHWAY, CNS
Dopamine release causes repetition of behaviours: classical conditioning/associative learning
Most affected by addictive drugs and behavioral addictions
Increases in DA SPECIFICALLY IN MESOLIMBIC **= may be related to schizophrenia
Decreases of DA SPECIFICALLY IN MESOLIMBIC=attention deficits
SOURCE: ventral tegmentum (VTA) to NAcc to hippocampus (HPC) to amygdala to PFC

Question 12

NAcc

Answer 12

nucleus accumbuns in basal ganglia: part of the striatum
motivated and goal driven behavior

Question 13

Causes and symptoms of parkinsons

Answer 13

Micheal J fox was the advocate, founder for the current parkinsons work done today
1. shaking hands usually first symptoms=tremors
2. earlier you develop parkinsons, worse it will be
3. hard to initiate first steps (though footprint stickers might be helpful) , but propensity to lean/run forward to prevent falling
As progresses – essential functions such as eating,
swallowing impaired
Cause: several genes have been implicated,
environment may also play a role
Gene environment interaction
Death of dopaminergic neurons in SN

Question 14

Joy milne

Answer 14

identified the PD scent: could predict people’s diagnosis since those people had more sebum than normal

Question 15

5HT function, synthesized from what, major pathway, major brain regions of that pathway

Answer 15

-synthesized from the amino acid tryptophan (abundant in
milk, pork, turkey, bananas etc.)
Function: Role in regulating waking activity, mood and aggression,
appetite, sleep, memory, respiration, pain perception, calming chemical
Serotonergic System: active in maintaining waking EEG patterns, changes in levels could = OCD (too little 5HT), tics (too much or too little 5HT), or schizophrenia (too much)
Abnormalities in brainstem 5-HT are linked to disorders like sleep apnea and SIDS (wakefulness issues)
Source: raphe nuclei in the reticular part of brain stem (activating part) to basically everywhere in the brain

Question 16

Low 5HT implications

Answer 16

depression

Question 17

GABA

Answer 17

Amico acids
plays in almost every aspect of function: “Workhorse of brain”=used more than anything else
GABA – main inhibitory NT ALMOST ALWAYS
* Learning and memory, brain development, in forebrain and cerebellum

Question 18

GLutamate

Answer 18

Amico acids
plays in almost every aspect of function: “Workhorse of brain”=used more than anything else
Glutamate: l;earning and memory, almost always excitatory, activate especially in HPC and cortex

Question 19

Two classes of neurotransmitter receptors and functions

Answer 19

Ionotropic receptor: embedded membrane protein that acts
as both a binding site for NT and a pore that regulates ion
flow (LIGAND GATED CHANNELS, when it binds a pore opens
Metabotropic receptor: embedded membrane protein with a
binding site for a NT
* Linked to a G protein: when NT binds, it activates G protein, that then activates other proteins = “Intracellular Signalling cascade” like a domino effect

Question 20

Ligand

Answer 20

bind to another molecule and change its shape: pore opens when NT binds

Question 21

G protein coupled receptors

Answer 21

GPCRS: G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior.

Question 22

Process of Ionotrophic receptor and transmitter binding

Answer 22

1. transmitter binds to binding site
2. Pore opens, allow influx or efflux of ions: changes the membrane potential to either create an IPSP OR EPSP

Question 23

Process f metabotrophic receptors coupled to an ion channel

Answer 23

1. Transmitter binds to receptor in both reactions: can activate gene expression, cause insertion of more channels, major mechanism for plasticity
2. The binding of the transmitter triggers the activation of a g protein in both reactions
3. The a subunit of the g protein binds to a channel, causing a structural change in the channel that allows ions to pass through it

Question 24

Process of metabotrophic receptors coupled to an enzyme

Answer 24

1. Transmitter binds to receptor in both reactions: can activate gene expression, cause insertion of more channels, major mechanism for plasticity
2. The binding of the transmitter triggers the activation of a g protein in both reactions
3. The a subunit binds to an enzymne, which activates a second messenger
4. The second messenger can activate other cell processes: activates DNA or forms new ion channel,

Question 25

Process of ACh at neuromuscular junction

Answer 25

1. an ap travels down the motor neuron = release of ACh into the synpatic cleft
2. ach binds to ACh receptors on the end plate (Motor endplates (MEPs) are important structural and functional interfaces between motor neurons and skeletal muscle fibers (MEPs receive electrical signals from motor neurons, generate endplate potentials, and consequently induce muscle contractions)
3. Ion channels open as a result=Na+ influxes into the cell
4. depolarization occurs as a result/an epsp: which opens a voltage gated sodium channel
5. this results in an ap for muscle contraction