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Flashcards in CNS Deck (37)
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1

CNS drugs can act on ___ and ___ receptors to produce an affect, causing one of what five actions?

pre and post synaptic receptors
1. production
2. storage
3. release
4. termination of action
5. activate or block receptors

2

CNS is very similar to ANS in terms of the actions that occur at the synaptic clefts... what 3 things make it different?

1. CNS= more complex and many more synapses
2. CNS= strong inhibitory neuron network constantly modulating transmission
3. CNS= More neurotransmitters

3

some drugs acting on the CNS do so by manipulating what two ion channel types?

1. voltage-gated (response to changes in membrane potential- channel types: Na, K, Ca)
2. ligand -gated: NTs bind receptors

4

ligand- gated ion channels: what are 3 types of receptor-channel coupling?

1. receptor acts directly on channel
2. Receptor is coupled to ion channel which is regulated by NTs and their receptors
3. Receptor is coupled to G protein that activates 2nd messenger...
-Cyclic adenosine monophosphate (cAMP)
-Inositol triphosphate (IP3)
-Diacylglycerol (DAG)

5

Neurotransmitter bind to postsynaptic neuron receptor, elicits response and trigger what two things?

EPSP and IPSP
excitatory post-synaptic potential and inhibitory post-synaptic potentials

6

what are our two excitatory NTs?

Ach, glutamate

7

what are our two inhibitory NTs?

GABA and glycine

8

EPSP is generated by...

Binding to receptor= small depolarization to stimulate EPSP
--> increased permeability of Na+
-->increase intensity and more presynaptic fibers activated
When enough excitatory fibers activated get complete depolarization of postsynaptic neuron

9

IPSP is generated by...

Stimulation if inhibitory neuron =release of inhibitory NTs to bind to postsynaptic neuron
--> increased permeability of K+ and Cl- channels
--> hyperpolarization (which stops that transmission from going on)
This diminishes action potential and neuron firing

10

3 characteristics of NTs found in CNS

1. Found in high concentrations in synaptic area
2. Release via calcium-dependent mechanism
3. Produce postsynaptic response resulting in physiologic activity

11

what are our 4 main types of NTs found in the CNS?

1. Ach
2. Amino acids
3. Monoamines
4. peptides

12

what are the amino acids in the CNS?

glycine, glutatame, GABA

13

what are the monoamines in the CNS?

Serotonin, histamine
Catecholamines:
Dopamine, Epinephrine, Norepinephrine

14

what are the peptides in the CNS?

endorphin, opioid peptides, substance P

15

binding of excitatory NT Ach causes ____ while binding of inhibitory NT GABA causes _____

depolarization (Na + enters cell)
hyperpolarization (Cl- enters cell)

16

what three receptor types does Ach bind to? excitatory or inhibitory?

Binds to M1 receptors: excitatory (like agonist)
Binds to M2 receptors: inhibitory (like antagonist)
Binds to Nicotinic receptors: excitatory (like agonist)

17

what does serotonin bind to and cause?

Bind to serotonin GPCR – 14 different receptors to date
Depending on receptor subtype can cause excitation or inhibition

18

what does histamine bind to and cause?

Bind to histamine GPCR – 4 (H1-H4)
Affect arousal, body temp, vascular dynamics, gastric acid secretion

19

what does dopamine bind to and cause?

Binds primarily to D2 receptor
Exerts slow inhibitory actions postsynaptically
Inhibits calcium channels presynaptically
-more in CNS than periphery

20

what does norepi bind to and cause?

Excitatory effects produced when activate α1 & β1
Inhibitory effects produced when activated α2 presynaptically

21

tell me about what we know about Epi?

Small amount in CNS
Physiologic properties not clearly defined

22

what does glutamate bind to and cause?

Excitatory
Bind to ionotropic (NMDA, AMPA, KA) and metabotropic (8– mGluRs) receptors
Excess attributes to damage and cell death

23

what does GABA bind to and cause? where is it located?

CNS-slow things down
Primary IPSP in the brain – inhibitory
Bind to GABAA or GABAB receptors

24

what does glycine bind to and cause? where is it located?

Primary IPSP in the spinal cord – Inhibitory
Bind to ionotropic glycine receptors

25

selectivity of a drug is based on what? more selective = ?

based on the fact that neurons with different functions have different neurotransmitters
more selectivity = less side effects

26

what are the downsides to the lipid solubility of CNS drugs?

lipid soluble to get into CNS...but that means they also readily cross the placenta and enter fetal circulation

almost all require hepatic metabolism to become polar (water soluble) for elimination/excretion
CYP450 enzymes and drug interactions needs consideration
This can impact clearance of CNS drugs, affect intensity and/or duration of their effect
lots of anti-epileptic have interactions

27

NT may inc Cl- conductance to cause?

inhibition

28

NT may inc K+ conductance to cause?

inhibition

29

NT may inc Na+ conductance to cause?

excitation

30

NT may inc Ca+ conductance to cause?

excitation