Amino Acids (General) Flashcards
Ionotropic Glutamate Receptors
- Receptor Type?
Ligand-Gate Ion Channel
Ionotropic Glutamate Receptors
- Subtypes?
NMDA Receptors
AMPA Receptors
Kainate Receptors
Metabotropic Glutamate Receptors
- Receptor Type?
G Protein Coupled Receptor
Metabotropic Glutamate Receptors
- Subtypes
Group 1
Group 2
Group 3
Ionotropic Glutamate Receptors
- Structure
4 Subunits with Pore Loop
16 Subtypes of Subunits
Ionotropic Glutamate Receptors
- NMDA Receptors
Ca2+ Flows through
- Blocked by Mg2+
- Requires Glycine for activation (Allosteric Modulator)
- Long Lasting Depolariszation
Ionotropic Glutamate Receptors
- AMPA Receptors
Fast Kinetics
- Short Lasting Depolarization
Excess Glutamate Activity?
Excess Ca2+ –> Excitotoxicity
–> Death of Neurons
Metabotropic Glutamate Receptors
- Group 1
Postsynaptic Receptors
Excitatory
Increase Ca2+
Metabotropic Glutamate Receptors
- Group 2 & 3
Presynaptic Receptors
Reduces synaptic excitability
GABA(A) Receptors
- Receptor Type
Ligand-Gated Ion Channels
GABA(A) Receptors
- Structure
- Location
Pentamer
Alpha-Beta-Alpha-Beta-Gamma
Found primarily Postsynaptically
GABA(A) Receptors
- Function
Fast, Long Lasting Inhibition
Allows Cl- to enter (Hyperpolarization)
GABA(A) Receptors
- Extrasynaptic vs Synaptic
Extrasynaptic Receptors have higher affinity for GABA than Synaptic Receptors
GABA(B) Receptors
- Receptor Type
GPCR
GABA(B) Receptors
- Structure
- Location
Dimeric Gi/Go
Located Presynaptically and postsynaptically
GABA(B) Receptors
- Function
Presynaptic: Inhibits Voltage Gated Ca2+ Channels
–> Decreases Transmitter Release
Postsynaptic: Opens K+ Channels
–> Hyperpolarization, less excitability
Glycine Receptor
- Receptor Type
- Structure
Ligand-Gated Cl- Channel
Pentameric
Glycine Receptor
- Function
Regulates:
- Respiratory Rhythms
- Motor Control
- Muscle Tone
- Pain Signalling
Dopamine Receptors
- Receptor Type
- Subtypes
- Acts where
GPCRs
- D1 = Gs
- D2 = Gi
D1 (D1, 5)
D2 (D2-4)
Acts both Presynaptically and Postsynaptically
D1
Causes postsynaptic inhibition (Despite being Gs)
- Increases AC –> Increased PKA –> Phosphorylates Ion Channels
- Ion Channels are blocked, preventing Na+ from passing –> Prevent Depolarization
- Inhibitory Effect
D2
Causes pre- and postsynaptic inhibition
- Decrease AC –> Decrease cAMP
Functions as inhibitory receptors on dopaminergic neurons
- ls also found on non-dopaminergic nerve terminals
Dopaminergic Pathway
(Motor Effects)
Nigrostriatal Pathways
(Substantia Nigra & Corpus Striatum)
- Dopamine controls/inhibits excitatory motor neurons
Dopaminergic Pathway
(Behavioural Function)
Mesocortical/Mesolimbic Pathways
- Dopamine activates reward pathways
- Dopamine is responsible for emotion and euphoria
Dopaminergic Pathway
(Neuroendocrine Function)
Neurohypophyseal Pathway
Hypothalamus secrete dopamine to inhibit prolactin release from pituitary
Dopaminergic Pathway
(Peripherally)
Dopamine plays a role in:
- Renal Vasodilation
- Myocardial Contractility
Dopamine Roles Summary
CNS:
- Motor Control
- Reward Pathways
- Prolactin Release Inhibition
- Nausea and Vomiting
PNS:
- Renal Vasodilation
- Myocardial Contractility
How long is Dopamine’s Half Life in Blood?
Not that long, has a short half life
