Trachte Neurotransmitter Systems Flashcards Preview

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Flashcards in Trachte Neurotransmitter Systems Deck (25):
1

Neurons contain 2 general types of channels

voltage gated
ligand gated

2

neurotransmitters typically of two types

ligand gated - open briefly, fast action potentials (ie glutamate)
metabotropic - interacts with GTP binding protein, modulate VG channels (i.e. ach)

3

Excitation is a ______ potential

depolarization

4

Inhibition is a ______ potential

hyperpolarization (usually involving G proteins)
also presynaptic inhibition

5

Steps of an action potential

at -70, Na flows in to -55 = threshold, then vg na open to let more flow in (want to get to +67) then Na inactivate and K open, K flows out to bring down again (to -93), hyperpolarizes and closes K channels, leak/atpases bring back to -70

6

concentrations of membrane


Nernst = 62/Z log (out/in)

in out E
Na 12 150 +67
K 150 5 -93
Cl 7 100 -71
Ca 0.01 2.5

7

Glutamate - stim or inh?

pre- can be inhibitory (metabotropic)
post - stimulatory, acts to increase cations within rec. neurons

8

GABA - stim or inh?

inhibitory
A - Cl channel (hyperpolarize)
B - augment K or inhibit Ca or inh AC

9

What happens when take away influence of GABA?

Overexcited (thus fear, anxiety) - physically overstimulated, neurons fatigued and confused

10

Glycine: inh or stim?

inhibitory of spinal cord and brian stem
receptor permeable to cl- (hyperpolarizes)

11

Strychnine is an example of Glycine antagonist. Action?

Glycine --> inhibits motor activity so inhibiting glycine --> increase motor activity (pesticide, poison --> spastic muscle, convulsions)

12

Hierarchical NT

glutamate, GABA, glycine

13

Diffuse NT

Acetylcholine, Dopamine, Norepinephrine, Serotonin, Opioids

14

Acetylcholine receptors

Nicotinic (Na channels depolarize, excitatory)
Muscarinic (metabotropic - reduce cAMP or increase Ca, increase K permeability, inh OR stim, cognition and memory)

15

Dopamine receptors

D1 - couples to Gs proteins to STIMULATE cAMP
D2 - Gi proteins to SUPPRESS cAMP (suppress GABA release - disinhibition)
antipsychotics antagonize, antidepressants prevent uptake so more dopamine (less GABA --> more movement)

16

location for dopamine synthesis

substantia nigra

17

LOCATION norepinephrine

locus coeruleus

18

action norepi

alpha2 receptors --> increase K conductance (inhibitory)
Can be used as muscle spasmolytics

other receptors - attention and arousal

19

Serotonin actions

5HT
5HT3 receptor = ionotropic, excitatory
5HT2a = metabotropic, block this receptor for psych tx, block UPTAKE to increase action here for antidepressants

20

serotonin location

raphe nucleus or midline pons

21

opioids action

decrease Ca or cAMP - mu receptor (also delta, kappa)
= inhibitory
works in spinal cord

22

potential steps of process drugs can work on

action potential; neurotransmitter synthesis; neurotransmitter storage; neurotransmitter metabolism; neurotransmitter release; neurotransmitter reuptake; neurotransmitter degradation; neurotransmitter receptors; and ion conductance.

23

Motor and sensory perception are typically _______ (consequences)

Hierarchical

Disruption at any level ablates the system
No redundant mechanisms

24

Monoaminergic systems tend to be _______

diffuse

25

pre-synaptic process

Presynaptic membrane depolarization activates Ca channels (voltage gated)
Ca entry into presynaptic neuron promotes docking of vesicles with plasma membrane
Releases vesicle contents
Chemical transmitter diffuses across synapse
Chemical transmitter binds to its receptor, briefly changing membrane potential