Excitatory and Inhibitory Neurotransmission Flashcards
Difference between an ionotropic receptor and a metabotropic receptor?
Ionotropic receptor = the receptor is the channel
(think Iono-iONEo)
Metabotropic receptor = the receptor and the channel are separate
These channels are tetramers
Glutamate
These channels are pentamers
GABA, Glycine, nicotine
What channel does ketamine block?
NMDA
What channel does phencylidine block?
NMDA
What does GABA-A receptor operate? (this is an ionotropic receptor)
The Cl- channel
What does the GABA-B receptor operate? (This is a metabotropic receptor)
The potassium channel
Which type of drugs are positive allosteric receptors of GABA-A receptors?
Benzodiazepines
= enhance Cl- entry =decrease rmp = enhance inhibitio in presence of GABA
Similar to benzodiazepines and potentiates the effect of GABA at the GABAA receptor
Barbiturates
agonist of the GABAB receptor so enhances the K current (and increases inhibition)
Baclofen
Which transmitter acts on the glycine ionotropic receptor? And what channel does it gate?
- Glycine
- Cl- channel
This is released by interneurones in spinal cord to inhibit antagonist muscles motorneurones
Glycine
the major excitatory neurotransmitter, acts on ionotropic receptors to allow Na and Ca in and K out of the cell, net result is an EPSP, depolarization, and excitation
Glutamate
the major inhibitory neurotransmitter, acts on ionotropic receptors to allow Cl into the cell, net result is an IPSP, hyperpolarization, and inhibition
GABA
a locally-acting neurone, typically releases GABA and so brings about an IPSP and inhibition, function is local processing of information
Interneurone
a neuron responsible for conveying signals to other parts of the brain, typically releases Glutamate and so brings about an EPSP
Projection neurone
What is spatial summation?
EPSPs and IPSPs are spatially distributed but timed together
i.e. all the excitation/inhibition occurs at once
What is temporal summation?
EPSPs occur in temporal sequence such that threshold is triggered
(i.e. might be excited-then inhibited then excited then excited , the potentials arrive one after the other instead of all at once)
