Chemical Signaling

Question 1

Otto Loewi is famous for his ____ experiment, through which he discovered the ____ (later identified as the ____)

Answer 1

Dream; “Vagusstoff”; Acetylcoline

Question 2

3 major classes of classical neurotransmitters

Answer 2

• Acetylcholine
• Monoamines
• Amino Acids

Question 3

5 features of classical chemical neurotransmitter:

Answer 3

1. Synthesized Presynaptic ally
2. Packed into vesicles (via proteins called vesicular transporters)
3. Bind to SELECTIVE postsynaptic receptors
4. Releases from vesicles in response to an action potential
5. There is a mechanism for signal termination

Question 4

Two ways that classical neurotransmitters are synthesized

Answer 4

• Chemical precursors (from diet)
• Enzymes catalyze the synthesis

Question 5

Two key examples of postsynaptic receptors

Answer 5

• Ionotropic: Ligand-gated
• Metabotropic: G-Protein coupled

Question 6

Ionotropic receptor receives neurotransmitters, then undergo ____ change, eventually opens up for ____ to flow through; They are typically ____ acting.

Answer 6

Conformational (structural); Ions; Fast

Question 7

Metabotropic receptor receives neurotransmitters, then ____-____ dissociates with the receptor, causing the ____ ____ to move to nearby ____ ____; Typically ____ acting.

Answer 7

G-protein; Alpha subunit; Ion channel; Slow

Question 8

Metabotropic are slow acting because of both the brief ____ in moving protein to ion channel and the ____ of 2nd ____ proteins (ex. Cyclic AMP)

Answer 8

Delay; activation; messenger

Question 9

Most neurotransmitter receptors in the brain are….

Answer 9

G-protein coupled (GPCR)

Question 10

Action potential causes large ____ and lead to the opening up of ____-____ ____ channels for an influx of ions, enabling the ____ to be conducted

Answer 10

Depolarization; Voltage-gated Ca2+; Signal

Question 11

The chemical signal can be terminated by ____ via ____ and ____-____ into the ____ cell by proteins called ____

Answer 11

Degradation; Enzymes; Re-uptake; Presynaptic; Transporters

Question 12

Classical neurotransmitters

Answer 12

• Acetylcholine (Vagusstoff)
• Monoamines
• Amino Acids

Question 13

Monoamines that are part of the classical neurotransmitter

Answer 13

• Catecholamines (dopamine, norepinephrine)
• Indolamine (serotonin)

Question 14

Amino acids part of the classical neurotransmitters

Answer 14

• GABA
• glutamate

Question 15

• Acetylcholine is synthesized by binding ____ ____ to a choline group
• Projection neuron: ____ ____; Interneurons: ____
• Packed into vesicles via the ____ ____ ____ (VAChT)

Answer 15

• Acetyl CoA
• Basal forebrain; striatum
• Vesicular acetylcholine transporter

Question 16

Receptors of acetylcholine include ____ (ionotropic) and ____ (metabotropic), and the signal are degraded by ____ ____ (AChE) which is very ____

Answer 16

Nicotinic; muscarinic; Acetylcholine esterase; efficient

Question 17

Monoamines are so called because they all have…

Answer 17

A NH group (amine)

Question 18

• Catecholamines are synthesized from ____ by utilizing a ____ ____ (TH), which can also be used as a ____ for Monoamines neurons
• Intermediate in synthesis of dopamine: ____ (also used to treat Parkinson’s Disease)
• Packed into vesicles via the ____ ____ ____ (VMAT)

Answer 18

• Tyrosine; tyrosine hydroxylase; marker
• L-DOPA
• Vesicular Monoamine transporter

Question 19

Norepinephrine is synthesized from ____ with the help of an enzyme called ____ ____-____ (DBH)

Answer 19

Dopamine; dopamine beta-hydroxylase

Question 20

____ by itself cannot cross the BBB, but L-DOPA can, which is why it is used for treating diseases.

Answer 20

Dopamine

Question 21

The primary method for eliminating monoamines is to ____ them by ____ located on ____ terminal or the synapse

Answer 21

Reuptake; transporters; presynaptic

Question 22

• The removal of Catecholamines are made possible by ____ ____ (DAT) and ____ ____ (NET)
• Once inside the presynaptic terminal, Catecholamines are either degraded by the enzyme ____ ____ (MAO) or re-packaged into ____ for re-release

Answer 22

• DA transporter; NE transporter
• Monoamine oxidase; vesicles

Question 23

The 2 main pathways for projection neurons of Catecholamines (DA)

Answer 23

• Mesocortical
• Mesotriatal

Question 24

Origin and primary targets of the mesocortical projection neuron (DA)

Answer 24

• Originates from the VTA (ventral regimental area)
• Primary targets: NAc (nucleus accumbens), prefrontal cortex, and hippocampus

Question 25

Origin and primary targets of the mesostriatal projection neuron (DA)
*In ____ ____, it is the first to degenerate

Answer 25

• Origin: Substantia Nigra (controls movement)
• Primary target: Striatum
• Parkinson’s Disease

Question 26

The 2 main families of DA receptors are… and they are both ___tropic

Answer 26

• D1 family: D1&D5
• D2 family: D2, D3, D4
• Metabo

Question 27

Origin and primary targets of the projection neuron (NE)

Answer 27

• Origin: Locus coeruleus (LC — also responsible for stress and panic)
• Primary targets: hippocampus, basal ganglia, prefrontal cortex

Question 28

The basal ganglia is comprised of…

Answer 28

• Striatum
• Nucleus accumbens (NAc — interface between motivation and action)

Question 29

The 2 main families of NE receptors are… and they are both ___tropic

Answer 29

• Alpha: 1&2
• Beta:1&2
• Metabo

Question 30

• Serotonin is a type of ____ synthesized from ____ with the help of ____ ____ (TPH)
• Packaged into vesicles by ____

Answer 30

• Monoamine; tryptophan; tryptophan hydroxylase
• VMAT

Question 31

The primary method for eliminating monoamines is through ____ by ____ (SERT) located on the ____ terminal or the synapse

Answer 31

Re-uptake; 5-HT transporter; presynaptic