Chemical Signaling Flashcards
Otto Loewi is famous for his ____ experiment, through which he discovered the ____ (later identified as the ____)
Dream; “Vagusstoff”; Acetylcoline
3 major classes of classical neurotransmitters
- Acetylcholine
- Monoamines
- Amino Acids
5 features of classical chemical neurotransmitter:
- Synthesized Presynaptic ally
- Packed into vesicles (via proteins called vesicular transporters)
- Bind to SELECTIVE postsynaptic receptors
- Releases from vesicles in response to an action potential
- There is a mechanism for signal termination
Two ways that classical neurotransmitters are synthesized
- Chemical precursors (from diet)
- Enzymes catalyze the synthesis
Two key examples of postsynaptic receptors
- Ionotropic: Ligand-gated
- Metabotropic: G-Protein coupled
Ionotropic receptor receives neurotransmitters, then undergo ____ change, eventually opens up for ____ to flow through; They are typically ____ acting.
Conformational (structural); Ions; Fast
Metabotropic receptor receives neurotransmitters, then ____-____ dissociates with the receptor, causing the ____ ____ to move to nearby ____ ____; Typically ____ acting.
G-protein; Alpha subunit; Ion channel; Slow
Metabotropic are slow acting because of both the brief ____ in moving protein to ion channel and the ____ of 2nd ____ proteins (ex. Cyclic AMP)
Delay; activation; messenger
Most neurotransmitter receptors in the brain are….
G-protein coupled (GPCR)
Action potential causes large ____ and lead to the opening up of ____-____ ____ channels for an influx of ions, enabling the ____ to be conducted
Depolarization; Voltage-gated Ca2+; Signal
The chemical signal can be terminated by ____ via ____ and ____-____ into the ____ cell by proteins called ____
Degradation; Enzymes; Re-uptake; Presynaptic; Transporters
Classical neurotransmitters
- Acetylcholine (Vagusstoff)
- Monoamines
- Amino Acids
Monoamines that are part of the classical neurotransmitter
- Catecholamines (dopamine, norepinephrine)
- Indolamine (serotonin)
Amino acids part of the classical neurotransmitters
- GABA
- glutamate
- Acetylcholine is synthesized by binding ____ ____ to a choline group
- Projection neuron: ____ ____; Interneurons: ____
- Packed into vesicles via the ____ ____ ____ (VAChT)
- Acetyl CoA
- Basal forebrain; striatum
- Vesicular acetylcholine transporter
Receptors of acetylcholine include ____ (ionotropic) and ____ (metabotropic), and the signal are degraded by ____ ____ (AChE) which is very ____
Nicotinic; muscarinic; Acetylcholine esterase; efficient
Monoamines are so called because they all have…
A NH group (amine)
- 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)
- Tyrosine; tyrosine hydroxylase; marker
- L-DOPA
- Vesicular Monoamine transporter
Norepinephrine is synthesized from ____ with the help of an enzyme called ____ ____-____ (DBH)
Dopamine; dopamine beta-hydroxylase
____ by itself cannot cross the BBB, but L-DOPA can, which is why it is used for treating diseases.
Dopamine
The primary method for eliminating monoamines is to ____ them by ____ located on ____ terminal or the synapse
Reuptake; transporters; presynaptic
- 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
- DA transporter; NE transporter
- Monoamine oxidase; vesicles
The 2 main pathways for projection neurons of Catecholamines (DA)
- Mesocortical
- Mesotriatal
Origin and primary targets of the mesocortical projection neuron (DA)
- Originates from the VTA (ventral regimental area)
- Primary targets: NAc (nucleus accumbens), prefrontal cortex, and hippocampus
Origin and primary targets of the mesostriatal projection neuron (DA)
*In ____ ____, it is the first to degenerate
- Origin: Substantia Nigra (controls movement)
- Primary target: Striatum
- Parkinson’s Disease
The 2 main families of DA receptors are… and they are both ___tropic
- D1 family: D1&D5
- D2 family: D2, D3, D4
- Metabo
Origin and primary targets of the projection neuron (NE)
- Origin: Locus coeruleus (LC — also responsible for stress and panic)
- Primary targets: hippocampus, basal ganglia, prefrontal cortex
The basal ganglia is comprised of…
- Striatum
- Nucleus accumbens (NAc — interface between motivation and action)
The 2 main families of NE receptors are… and they are both ___tropic
- Alpha: 1&2
- Beta:1&2
- Metabo
- Serotonin is a type of ____ synthesized from ____ with the help of ____ ____ (TPH)
- Packaged into vesicles by ____
- Monoamine; tryptophan; tryptophan hydroxylase
- VMAT
The primary method for eliminating monoamines is through ____ by ____ (SERT) located on the ____ terminal or the synapse
Re-uptake; 5-HT transporter; presynaptic
