Neuro - Neurotransmitters
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- Fast excitatory NT?
- glutamate
- Fast inhibitory NT?
- GABA
- What receptor(s) does glutamate bind, and what type of receptors are they?
- AMPA/kinate OR NMDA; ionotropic receptors (receptors are actually part of ion channel)
- How does glut-AMPA/kinate binding excite the cell?
- Na enters, and some K exits
- How does glut-NMDA binding excite the cell?
- allows Na AND Ca to enter (which can activate Ca dependent 2nd messanger systems)
- What ion blocks the NMDA receptor, and under what conditions does it block/unblock?
-
Mg -> "voltage dependent Mg block"
blocks when hyperpolarized, unblocks when cell depolarizes - What receptor(s) does GABA bind?
- GABA(A) and GABA(B)
- How does GABA-GABA(A) binding elicit an inhibitory response?
- GABA(A) is an ion channel that lets Cl into the cell, hyperpolarizing it
- How does GABA-GABA(B) binding elicit an inhibitory response?
-
GABA(B) act through G-protein to activate K channels (let K out = hyperpolarize)
*responsible for slow/late inhibitory PSPs* - Does GABA ALWAYS hyperpolarize the cell? Why?
- NO. If the cell membrane potential is initially NEGATIVE to the reversal potential of GABA(A)(-75mV) or GABA(B)(-115mV), GABA will slightly depolarize the cell, but it is still inhibitory b/c it resists mvt towards the activation potential threshold
- What are the main neuromodulatory NTs?
- Ach, 5HT, NE, DA, histamine
- What do neuromodulators do?
- change the firing pattern and/or excitability of neurons
- What are the equilibrium potentials of Ca, Na, Cl, K?
-
Ca: +125mV
Na: +60mV
Cl: -75mV
K: -100mV - In what disease is there depleted ACh levels?
- Alzheimer's
- What NT is known as the prolactin-inhibiting factor?
- DA
- Where are the two main places in the brain that is DA found?
- arcuate nucleus of the hypothalamus, and the SNpc/ventral tegmental area
- Which DA receptor serves an excitatory function?
- D1 (activates AC)
- Which DA receptor serves an inhibitory function?
- D2 (inhibits AC)
- What receptors do antipsychotics block?
- D2
- What disease is characterized by the loss of nigrostriatal dopaminergic neurons?
- Parkinson's
- Where are norepinephrinergic neurons found in the highest concentration?
- Locus ceruleus of the midbrain and pons
- What is the catecholamine hypothesis of mood disorders?
- reduced NE activity is related to depression and increased NE activity is related to mania
- Which NT plays a role in anxiety states?
- NE
- Where are 5HT neurons found?
- raphe nuclei
- What is the permissive serotonin hypothesis?
- decreased 5HT activity causes depression and insomnia, increased levels cause mania
- Dysfunction of what NT is thought to underlie OCD?
- 5HT
- What receptors to SSRIs block?
- 5HT(IA) and 5HT(2)