4 - Neurotransmitters

Question 1

What is a receptor potential?

Answer 1

graded potential produced by activation of a sensory receptor, can be depolarizing or hyperpolarizing

Question 2

What is postsynaptic potential?

Answer 2

release of vesicles at the presynaptic terminal as a response to an action potential, changing the postsynaptic potential; if excititory will be depolarizing and if inhibitory will be hyperpolarizing.

Question 3

What are the similarities between receptor potentials and postsynaptic potential? (2)

Answer 3

both potentials are graded changes in membrane excitability that decay away from the site of stimulus.

membrane potential must reach threshold level at the critical point of the axon (initial segment, axon hillock) that contains the voltage-gated ion channels, otherwise no AP will be produced

Question 4

What are the two possible mechanisms neurotransmitters have of influencing the postsynaptic cell?

Answer 4

Ionotropic

Metabotropic

Question 5

Where are Ionotropic receptors located and how do they activate?

Answer 5

localized within the actual ion channel

Question 6

Where are Metabotropic receptors located and how do they activate?

Answer 6

receptors are located at some point on the membrane but activate an ion channel some distance away via a second messenger system.

Question 7

What does activation of a Metabotropic receptor to activate an ion channel?

Answer 7

some internal cellular mechanism that may be long acting via changes in enzyme/protein expression.

Question 8

What are the 3 classes of compounds?

Answer 8

Fast neurotransmitters
Neuropeptides
Non-traditional neurotransmitters

Question 9

Are Fast Neurotransmitters ionotropic or metabotropic?

Answer 9

often associated with ionotropic receptors, although may also act on metabotropic receptors (such as catecholamines)

Question 10

Are Fast Neurotrasnmitters Excitatory or Inhibitory? Example?

Answer 10

Excitatory (ACh, glutamate, epinephrine)

Inhibitory (GABA, glycine)

Question 11

Are Neuropeptdies ionotropic or metabotropic? Examples?

Answer 11

metabotropic (enkephalin, calcium binding protein, substance P)

Question 12

Are Fast Neurotransmitters, Neuropeptides, or Non-traditional neurotransmitters more complex AA peptides from small to large?

Answer 12

Neuropeptides

Question 13

What are Non-traditional neurotransmitters?

Answer 13

nitric oxide, eiconasoids (prostaglandins, cannabinoids)

Question 14

Do Fast Neurotransmitters, Neuropeptides, or Non-traditional neurotransmitters affect adjacent cells?

Answer 14

Non-traditional neurotransmitters

Question 15

Neurotransmitters are co-localized with ___ in axonal terminals.

Answer 15

neuropetides

Question 16

What is an example of Neurotransmitters co-localized with neuropeptides?

Answer 16

GABA/calbindin in the frontal lobe and GABA/paryalbumin in the occipital lobe

Question 17

What is the function of colocalization? (2)

Answer 17

not clear but some indication is that the peptide acts as a neuromodulator by modifying the activity of the cell during neurotransmission,

as well as prolonging membrane activity.

Question 18

T/F: the presynaptic receptor determines whether the neurotransmitter will be excitatory or inhibitory.

Answer 18

False: the POSTSYNAPTIC receptor determines whether the neurotransmitter will be excitatory or inhibitory.

Question 19

what on the postsynaptic receptor determines whether the nerurotransmitter will be excitatory or inihibotory? example?

Answer 19

what type of ion channel the receptor is located on

Excitatory: Acetylcholine with Na+ channels
Inhibitory: GABA and glycine with Cl- channels

Question 20

What are the specific transmitters to know? (4)

Answer 20

1. acetycholine
2. gamma-aminobutyric acid (GABA)
3. catecholamines
4. glutamate