Neurophysiology L5 Flashcards
Indirect Coupling (not metabotropic)
G-protein control an ion channel directly. Less modulated then metabotropic coupling
Indirect coupling can also refer to metabotropic
Ligand -Gated Channel
Another name for ionotropic
G - Protein Mechanism
- Inactive G protein has its alpha beta gamma subunits together and GDP bound
- Ligand binds receptor and G protein associated
- The GDP is replaced with GTP thus breaking the alpha from the Beta Gamma
- Subunits go off to cause other results
- once hydrolyzed back to GDP the G protein comes back together
G-Protein – Gs
Activated Adenyl Cyclase (AC)
goes to activate cAMP which can act on an ion channel or go to activate a protein kinase
Phosphodiesterase (PDE)
Breaks down cAMP thus showing a way of modulation. It will stop the path
Caffeine inhibits PDE so cAMP goes up
G-Protein – Gc
Activated Guanylate cyclase (GC) to make cGMP
Gi is an example of this in the eye
G-Protein – Gi
Inhibits AC thus decreasing cAMP and modulation of ion channels
G-Protein – Gq
Activated Phospholipase C (PLC) thus cleaving diacylglycerol to DAG and IP3
IP3 goes to release calcium from ER
Calcium with DAG go to activate protein kinase C
G-protein – Golf
Activated by odors increases cAMP directly increasing sodium and calcium permeability. leading to depolarization. Golf is a specific Gs
G-protein – Geye (in the eye)
G-protein in retina called transducin activated by rhodopsin. activates a PDE hydrolyzing cGMP closing Na and hyper polarizing
NT - Dopamine (classification, type of receptor used)
Biogenic Amine, Several receptors all G-protein Coupled
Result of Low Dopamine
Parkinsons - relieved with DOPA
Result of High Dopamine
Leads to schizophrenia. so use receptors to block
Effect of Cocaine and Amphetamines
Block re-uptake of Dopamine so remains in cleft. dopamine leads to pleasure
Serotonin (classification and receptor)
Many receptors is a biogenic Amine.
Lack of Serotonin Results
Leads to depression. Treat with SSRI. it inhibits serotonin reuptake
MDMA/ LSD
agonist of serotonin by activating receptor. Causes euphoria.
Production of Serotonin
Produced from tryptophan and oxidized by MAO
Histamine (classification and receptors)
Produced by decarboxylation of histidine 3 receptors. involved in allergic reactions. Biogenic amine
Glutamate As a NT (where seen and receptors)
seen in many excitatory
seen in brain for memory
Amino acid has 3 ionotropic receptors
- Kainate, AMPA and NMDA
NMDA and AMPA process
NMDA - both ligand and voltage gated
What happens
- pore is blocked by Mg2+ until depol to -60
- glutamate comes in binds AMPA and not until multiple stimulations on the AMP Adoes it Depol and reach causing NMDA to open and creating a more slowly sustained response
GABA (Receptors and Category)
Amino Acid category . Major inhibitory in brain. formed by glutamate.
GABAa and GABAb
GABAa - ionotropic increases permeability to Cl opposing depolarization
GABAb- Metabotropic through Gi protein that decrease permeability to Ca and Increases to K
Barbiturates and benzodiazepins
they perpetuate inhibition by opening gCl opposing depolarization
Glycine as a NT
Acts by Increasing gCl and is inhibitory and seen in spinal cord
Substance P
Pain stuff excess can cause depression
Opioid Peptides (receptors and category)
Neuroactive peptides
seen in feeling of euphoria
Acts on Kappa Nu and Delta Receptors
- which act on G proteins they will suppress pain by inhibiting VGCaC and increase K conductance
NO (Nitric Oxide) (what it does, and how to potentiate)
Causes Vasodilation.
Activated Guanylate cyclase —> to a protein kinase
lifetime is short but could possibly be used to communicate post synaptic to presynaptic
To potentiate use a blocking of PDE like viagra
Purines - ATP And Adenosine
act on G-protein or ligand gated channel. Adenosine is a CNS depressant
