Physiology of nerve and glial cells

Question 1

which nerve fiber is the fastest conducting?

Answer 1

the A-alpha

Question 2

which nerve fiber is the slowest conducting ?

Answer 2

the C fibers

Question 3

neurotransmitter for EPSP?

Answer 3

glutamate

Question 4

which are the receptors for EPSP?

Answer 4

• ionotropic receptors
  AMPA
  NMDA
• metabiotropic receptors

Question 5

characteristics of AMPA?

Answer 5

• permable to univalent cations only, like Na+

Question 6

characteristics of NMDA?

Answer 6

• Permable to univalent cations and calcium (divalent)
• depolarization must have already occured in these channnels to open.
• there response is stronger.

Question 7

characteristics of matebotropic receptors?

Answer 7

• 7 TM GPCRs.
• eight total, known as mGluR 1-8
• all GI except 1 and 5
• signaling is much slower than w/ ionotropic receptors

Question 8

What does IPSP do?

Answer 8

• they hyperpolarize or stabalize the membrane potential

Question 9

what kind of channels are there for IPSP?

Answer 9

typically k+-channel or ligand-gated chloride channel

Question 10

whats the neurotransmitter for IPSP?

Answer 10

its GABA

Question 11

whats the receptor for IPSP?

Answer 11

• GABAa- receptor

- GABAb-receptor

Question 12

characteristics of GABA a-receptor?

Answer 12

• pentameric ligand gated Cl-channel

- used in many tranquliizing drugs

Question 13

characteristics of GABAb-receptor?

Answer 13

• Gi-coupled
• they open the inward-rectifying K+-channels
• they create a slower depolarization

Question 14

Whats the presynaptic inhibition?

Answer 14

Its where inhibatory neurotransmitter is released onto and inhibits an exitatory axon terminal.–> it reduces amoount of NT released–> smaller AP in PSN

Question 15

retrograde signaling?

Answer 15

• occurs w/ endocannabinoid system via CB1-receptor and 2-AG
• PSN stilumated w/ Glu triggering following cascade
  mGlur5–>Gq–>PLC–> IP3 + DAG–>DAG lipase–>2-AG
• 2 AG diffuses across synaptic cleft to presynaptic Glu neuron–>CB1R—> inhibition of glu release.

Question 16

non-adapting neuron?

Answer 16

• quickly depolarize and repolarize

- can maintain high frquency of AP

Question 17

adapting neuron?

Answer 17

• have slowly activating voltage gated K+channels that open.

- provide some resistance to depolarization making the ap frequency decrease.

Question 18

rythmic bursting neuron?

Answer 18

• have voltage gated Ca2+ channels and Ca2+-activated K+channel
• they hyperpolarize the neuron
• once Ca2+ pumped out of cell, new burst can occur

Question 19

non-rythmic ( burst) neuron?

Answer 19

• An EPSP leads to T-type ca2+ channles opening–>ca2+ influx and a quick burst of ap before the t-tubule channel inactivated.
• Iportant in thalamic activation

Question 20

whats synaptic plasticity?

Answer 20

• How a synapse may be more or less sensetive depending on its previous avtivity

Question 21

whats synaptic strength?

Answer 21

the mean amplitude of the postsynaptic response

Question 22

Synaptic facilitation?

Answer 22

<1 sec, increases in synaptic strenght after an AP series due to high [ca2+] remaining in presynaptic terminal

Question 23

Long term potentials?

Answer 23

• can increase synaptic strength for hours to days

-