Lecture 10

Question 1

Opening of ion channels in neurotransmitters results in graded _____/_____ which propel the next action potential wave.

Answer 1

IPSPs ; EPSPs

Question 2

Neurotransmitters receptors are _____tropic and _____tropic

Answer 2

1. ionotropic (ligand gated)
2. metabotropic (G-protein linked)

Question 3

T/F:

Metabotropic channels use the ligand gate method (lock and key).

Answer 3

FALSE

Question 4

T/F:

There are more than 100 different neurotransmitters receptors, meaning there are 100 major subtypes.

Answer 4

FALSE. Only TWO major subtypes (iono and metabo)

Question 5

Ionotropic receptors use _____ gated channels, causing them to be relatively (fast/slow)

Answer 5

ligand gated channels ; fast

Question 6

Name the three major NT that bind to ionotropic receptors:

Answer 6

1. ACh
2. Glutamine
3. GABA

Question 7

Metabotropic receptors use ___ coupled proteins, causing them to be relatively (fast/slow)

Answer 7

G-coupled protein ; slow
NT causes activation in effector pathways

Question 8

Name the six ions are involved in metabotropic mechanisms:

Answer 8

1. ACh
2. Glutamine
3. GABA
4. Serotonin
5. Dopamine
6. Norepinephrine

Question 9

G proteins are (inhibi/excita)tory:

Answer 9

INHIBITORY

Question 10

Ionotropic receptors are composed of #-# subunits:

Answer 10

4 to 5

Question 11

T/F:

Metabotropic receptors consist of pores.

Answer 11

FALSE

Question 12

Voltage gated channels are more (selective/open) than ionotrobic channels.

Answer 12

selective

Na+ and K- pass through both ACh receptors

Question 13

After ligands bind to ionotropic receptors, it changes _____.

Answer 13

shape

Question 14

Ionotropic receptors can sustain (AP/IP+EPSPs)

Answer 14

EPSP and IPSPs

receptor dependent

Question 15

When there is no net flow of ions, it is due to ____ and _____ currents.

Answer 15

equal ; opposite

Question 16

When vM is more negative than ERev, current flows (outward/inward).

Answer 16

inward

Question 17

When vM is more positive than ERev, current flows (outward/inward).

Answer 17

outward.

Question 18

Local potentials decrease with _____

Answer 18

distance.

Question 19

Limited external Ca2+ have voltage gated Ca2+ channels which cannot effectively release neurotransmitters but 1 to 2 ______ periodically

Answer 19

vesicles

(i.e.: 1x = 1 vesicle)

Question 19

A miniature endplate potential (MEPP) is when a single ______ randomly releases ____ “quantum”

Answer 19

vesicle ; ACh

Question 20

T/F:

40mV in quantal analysis is the fail safe for NMJ.

Answer 20

True.

Always produces AP at the endplate, contracting the muscle.

Question 21

Compared to quantal release of ACh at the NMJ, CNS synapses are (small / large)

Answer 21

Small.

Due to 1-10 vesicles per AP.

Question 22

IPSPs hyperpolarize through two ways:

Answer 22

1. influx of Cl-
2. outflux K+
   (shift Vm AWAY from firing threshold)

Question 23

EPSPs depolarize when:

Answer 23

Na+ influx causes channels to open, allowing vM to travel to the firing threshold.

Question 24

Anything that opens the membrane and makes the inside more negative makes the action potential (inhibi/excita)tory This (adds/subtracts) to our depolarizing potential, (inc/dec) length constant.

Answer 24

inhibitory ; subtracts from potential ; decreases length constant

Question 25

Anything that prevents potassium from going out of the membrane makes the inside more (negative/positive). Therefore, this makes the ____ ____ longer, increasing our depolarizing effect.

Answer 25

Membrane positive ; length constant longer

Question 26

The K+ and Cl- ion going OUT can make the inside of a neuron membrane more (+/-).

Answer 26

NEGATIVE

Question 27

Metabotropic receptors typically result in K+ channels opening. This generally leads to an (inhibitory/excitatory) response

Answer 27

inhibitory

Question 28

T/F: Metabotropic receptors cause EPSPs/IPSPs.

Answer 28

FALSE. Ionotrobic do!

Question 29

Synaptic transmission by metabotropic receptors are called _______.

Answer 29

modulation only for EPSP effectiveness

Question 30

T/F: Ion channel activation is fast than using an enzymatic second messenger:

Answer 30

TRUE *both still slow compared to transmitter gated (lock and key)

Question 31

Norepinephrine is an example of a (ionotropic/metabotropic) receptor.

Answer 31

metabotropic

Question 32

NE receptors are expressed in the heart and part of "fight or flight". This is defined as the (para/sympa)thetic system.

Answer 32

Sympathetic

Question 33

ACh receptors are expressed in the heart as part of "rest and digest". This is defined as the (para/sympa)thetic system.

Answer 33

parasympathetic

Question 34

Shunting with GABA alpha channels generally does what to membrane depolarization?

Answer 34

It keeps the channels open for longer, causing decreased resistance, dampened excitation, and reduced effects.

Question 35

Facilitation with K+ channels generally does what with membrane depolarization?

Answer 35

It closes the channels as soon as it can, causing increased resistance, further excitation, and increased effectiveness.

Question 36

GCPRs use ____ transmembrane domains

Answer 36

7

Question 37

GCPRs have a broader modulatory state such as:

Answer 37

altering the internal state or regulating ion channels.

Question 38

Name one AcH ionotrobic example and one metabotrobic example:

Answer 38

iono: Nicotenic metabo: Muscarinic

Question 39

Name one GLU ionotrobic example and one metabotrobic example:

Answer 39

iono: iGluRs metabo: mGluRs

Question 40

Name one GABA ionotrobic example and one metabotrobic example:

Answer 40

iono: GABA Alpha metabo: GABA Beta

Question 41

IPSPs and EPSPs translate:

Answer 41

chemical "messages" into vM

Question 42

IPSPs and EPSPs are governed by:

Answer 42

reversal potential monitors

Question 43

Reversal Potential is the critical balance point where:

Answer 43

net ionic current through a channel equals zero (equal but opposite inputs)

Question 44

In the CNS, a single EPSP is too small to hit threshold. Therefore, the brain can reach summation at -55mV in what two ways?

Answer 44

1. Spatial Summation 2. Temporal Summation

Question 45

Spatial Summation is the cause of:

Answer 45

the arrival of MANY EPSPs at the SAME time on different locations of a dendrite (i.e. there's a concert at 6:00pm and people show up at the same time but park different places to cause less congestion).

Question 46

Temporal Summation is the cause of:

Answer 46

high-frequency EPSPs rapidly ADDING to the same synapse (i.e. iShowSpeed at Kenwood Mall)

Question 47

Summation must be sufficient to cause any effect at the ____ ___- aka the spike-initiation zone.

Answer 47

axon hillock

Question 48

Success to depolarize our membrane heavily relies on dendritic _______ and _______.

Answer 48

properties ; conductance

Question 49

In the exponential voltage decay equation, the time constant (Resistance x Capacitance) dictates what?

Answer 49

how fast the circuit discharges (falls and returns to initial resting)

Question 50

In the exponential voltage decay equation, the exponent (determines rate of decay) reveals a negative sign when the value (increases/decreases).

Answer 50

decreases

Question 51

Shunting occurs when the opening of GABA Alpha channels increases _____ conductance.

Answer 51

Cl-

Question 52

Shunting allows some depolarizing current to _______ before reaching the soma.

Answer 52

leak

Question 53

Closing leak channels _____ the signal, increasing resistance and length to facilitate ______.

Answer 53

increases signal ; facilitates propagation

Question 54

Modulation effects what?

Answer 54

effectiveness of other inputs

Question 55

We can achieve modulation through what two methods?

Answer 55

1. using direct G proteins to "shake up" ion channels 2. have an enzyme drive second-messengers

Question 56

What signaling is the slowest and most complex?

Answer 56

second messenger transmitter > ionotropic > g protein > second mess