lab 10

Question 1

why are drugs that act on the CNS invaluable therapeutically?

Answer 1

bc they can produce specific psychological and physiological effects

Question 2

drugs that affect the CNS can,,,,,

Answer 2

selectively relieve pain, reduce fever, suppress disordered movements, induce sleep or arousal, reduce the desire to eat, or allay the tendency to vomit

Question 3

______ allows modern surgery to be possible

Answer 3

general anesthetics

Question 4

in the CNS, receptors to most synapses are coupled to what?

Answer 4

ion channels

Question 5

what are neurotransmitters?

Answer 5

chemical messengers that bind to postsynaptic membrane receptors.
results in a RAPID and TRANSIENT opening of ion channels which allows ions to move inside and outside of the cell membrane

Question 6

what occurs when ions move into/out of the cell membrane?

Answer 6

this alters the postsynaptic resting membrane potential which generates an ACTION POTENTIAL

Question 7

how can neurotransmitters be classified

Answer 7

either as excitatory or inhibitory (depending on the nature of the action)

Question 8

the stimulation of EXCITATORY neurons causes what?

Answer 8

the movement of sodium ions into the membrane, resulting in DEPOLARIZATION of the postsynaptic membrane

this EPSP (excitatory postsynaptic membrane potential) leads to the generation of an action potential

Question 9

when inhibitory neurons are stimulated, what occurs?

Answer 9

a movement of CHLORIDE ions into the cell membrane and/or POTASSIUM ions OUT of the cell membrane

this causes HYPERPOLARIZATION of the postynaptic membrane. IPSP generated which BLOCKS the generation of an action potential if the resting potential becomes too negative

Question 10

true or false

most neurons in the CNS receive only IPSP input

Answer 10

false – both EPSP and IPSP input

Question 11

most neurons in the CNS receive both IPSP and EPSP input.

thus….

Answer 11

several neurotransmitters may act on the same neuron, but each to its own specific receptor

Question 12

true or false

only 1 neurotransmitter can act on a neuron at a time

Answer 12

FALSE

most neurons receive both EPSP and IPSP input, thus SEVERAL neurotransmitters may act on 1 neuron, but each to their own specific receptor

Question 13

name 3 drugs that cause hyperpolarization

Answer 13

GABA
barbiturates
chlorpromazine

Question 14

name 2 drugs that cause depolarization

Answer 14

caffeine
PTZ

Question 15

drugs that cause hyperpolarization are called ______ and generate ____

Answer 15

depressants
generate IPSP

Question 16

drugs that cause depolarization are called ___ and generate ____

Answer 16

stimulants and generate EPSP

Question 17

in hyperpolarization, what ions are moving?

Answer 17

chloride into the cell and/or potassium out of the cell

Question 18

give the mV during hyperpolarization

Answer 18

-90mv

Question 19

give the mv of the normal resting membrane

Answer 19

-65 - -70mv

Question 20

give the mV of a depolarized membrane

Answer 20

+30mv

Question 21

what ions are moving in depolarization

Answer 21

sodium comes in, and after the sodium channel closes, potassium goes out of the cell

Question 22

neurotransmitters can produce how many types of impulses?
name them

Answer 22

2

EPSP - excitatory postsynaptic potential

IPSP - Inhibitory postsynaptic potential

Question 23

dopamine and ____ generate an ____

Answer 23

acetycholine

EPSP

Question 24

GABA and _____ generate an _____

Answer 24

serotonin
IPSP

Question 25

EPSP results in and initiates.... IPSP results in and initiates...

Answer 25

EPSP results in depolarization and the initiation of an action potential IPSP results in hyperpolarization and the INHIBITION of an action potential

Question 26

___ and ____ generate an EPSP

Answer 26

dopamine and acetylcholine

Question 27

___ and ___ generate an IPSP

Answer 27

GABA and serotonin

Question 28

EPSP controls the ___ of ___ ions

Answer 28

inflow of sodium ions

Question 29

IPSP controls the ___ of ___ ions

Answer 29

outflow of potassium ions inflow of chloride ions

Question 30

what is dopamine?

Answer 30

a neurotransmitter that is released in the DOPAMINERGIC neurons generates an EPSP, leading to EXCITATORY EFFECTS

Question 31

Name an antagonist that competes with dopamine and what they can be used as

Answer 31

CPZ - chlorpromazine is an antagonist to dopamine at the D2 receptors can be used as neuroleptic agents

Question 32

give 3 components of the neuroleptic response of CPZ (chlorpromazine)

Answer 32

1. decreases agitation 2. drowsiness 3. dizziness

Question 33

true or false caffeine is a stimulant

Answer 33

true

Question 34

caffeine is a ___ antagonist

Answer 34

adenosine

Question 35

how is caffeine a stimulant?

Answer 35

it further enhances excitatory effects by affecting various receptors in the neuron that are responsible for dopamine levels in synapse and blood stream IT INCREASES DOPAMINE LEVELS

Question 36

what does adenosine do

Answer 36

it controls the release of dopamine does this by binding to the adenosine receptor at the axon terminal and REDUCES dopamine release

Question 37

explain how caffeine is an antagonist to adenosine

Answer 37

caffeine binds to adenosine receptors and thus causes dopamine to be released and dopamine receptors to open up for binding (adenosine inhibits the release of dopamine and caffeine does the opposite)

Question 38

what does GABA stand for

Answer 38

gamma-aminobutyric acid

Question 39

what is GABA

Answer 39

a neurotransmitter released in GABA-aminergic neurons acts to generate an IPSP

Question 40

true or false GABA is a neurotransmitter that acts to generate an EPSP

Answer 40

FALSE IPSP

Question 41

how does GABA generate an IPSP

Answer 41

when GABA binds to 2 possible receptors -- GABA-A and GABA-B

Question 42

what are the overall effects when GABA binds to GABA A or GABA B

Answer 42

sedation anxiolytic muscle relaxation anti-seizure

Question 43

name 2 GABA agonists and explain how they work

Answer 43

barbiturates and benzodiazepines they will enhance the effect, but ONLY WHEN GABA IS PRESENT

Question 44

name a GABA antagonist

Answer 44

PTZ (pentylenetetrazole)

Question 45

explain how PTZ is a GABA antagonist

Answer 45

antagonizes the effects of GABA due to competition at the receptor site stimulates the CNS

Question 46

explain the GABA A receptor and the GABA B receptor

Answer 46

GABA A = ligand gated ion channel - ionotropic - forms Cl- channel GABA B = GPCR

Question 47

binding to the GABA A receptor results in...

Answer 47

increased Cl- conductance causes sedation, anxiolytic activity, muscle relaxation, and anti seizure

Question 48

binding to GABA-B receptor and g protein results in.....

Answer 48

K+ conductance inhibitory in nature

Question 49

name a GABA antagonist

Answer 49

PTZ (pentylenetetrazole)

Question 50

true or false barbiturates are GABA agonists and result in IPSPs

Answer 50

true

Question 51

tonic vs clonic convulsion

Answer 51

tonic = all paws are extended clonic - front and rear paws drawn in and extended out alternately

Question 52

what is the antidote for convulsions caused by PTZ

Answer 52

2x dose of pentobarbital