Neurotransmision s and r

Question 1

Describe the information flow in neurons:

Answer 1

Information is received form the dendrites; Processed (summed) at the axon hillock; if triggered the action potential travels down to axon; to the synaptic cleft

Question 2

Transmitters released from the nerve terminal activates what? This causes what?

Answer 2

Transmitters released from the nerve terminal activates post-synaptic receptors and causes an influx of ions or activation of second messengers

Question 3

in the cycle of transmission of a neurotransmitter describe the step from synthesis to just before release

Answer 3

Synthesis in cell body; anterograde transportation to nerve ending; uptake into synaptic vesicles; storage in synaptic vesicles; release to synaptic cleft;

Question 4

in the cycle of transmission of a neurotransmitter describe the step from release to degradation

Answer 4

Released to synaptic cleft; binding to and activation of post-synaptic receptors; the neurotransmitter can then be processed in one of three ways Extracellular enzyme destruction; reuptake direct into the terminal OR Reuptake into the cellular compartment then converted to an inactive metabolite and reused as needed;

Question 5

what is the extremely simplified cycle of neurotransmission?

Answer 5

Release-> Action (receptor binding) -> disposal (re-uptake)

Question 6

What are the three main types of neurotransmitters?

Answer 6

Excitatory (+ firing likelihood); inhibitory (- firing likelihood); neuromodulators

Question 7

the likelihood of action potential is determined by? Where is this determination made?

Answer 7

Likelihood of action potential is determined by the summation of all inputs At the Axon hillock

Question 8

What are the two most widely used amino acid transmitters in the CNS? Generally what is there function?

Answer 8

Glutamate (excitatory); GABA (inhibitory)

Question 9

GABA and Glutamate can be what?

Answer 9

Interconverted by a single enzymic step

Question 10

Both GABA and Glutamate are derived from what cycle? What molecule can they be converted from?

Answer 10

The TCA cycle; Alpha-Ketoglutarate -> Glutamate -> GABA -> Succinate

Question 11

Glutamate is involved in what?

Answer 11

Learning and memory; many neuro-psychiatric diseases

Question 12

GABA-alpha receptor is the stir of action of what kind of drugs? Give some examples

Answer 12

GABA-alpha receptor is the site of action of many psychoactive drugs including; alcohol; barbiturates; tranquilizers

Question 13

in excitotoxicity there is an imbalance between?

Answer 13

There is an imbalance between excitatory and inhibitory signals;

Question 14

What is the most common Neurotransmitter in the peripheral nerves?

Answer 14

Acetylcholine (Ach)

Question 15

Acetylcholine is synthesised from what? This process requires what and utilises what enzyme?

Answer 15

Choline; The process requires ATP and the enzyme that is used is choline acetyltransferase

Question 16

what are the two main Catecholamine neurotransmitters?

Answer 16

Dopamine; noradrenaline

Question 17

Catecholamine’s are derivatives of what neurotransmitter?

Answer 17

Tyrosine

Question 18

Dopamine receptors can do what to cAMP? What are the receptor types for each?

Answer 18

both increase or decrease cAMP; D1 like receptors (D1 and D5) increase while D2 like (D2; D3 and D4) decrease

Question 19

antipsychotics are D2 what? Antiparkinsonian are D2 what

Answer 19

antipsychotics are D2 antagonists; Antiparkinsonian drugs are D2 agonists;

Question 20

cocaine and amphetamines block what?

Answer 20

Dopamine transporter

Question 21

Peptide transmitters precursors are synthesised in the what? What happens to them post releases?

Answer 21

Peptide transmitter are synthesised in the Golgi apparatus; post realise they are degraded in the synaptic cleft they are not reused

Question 22

Fast Release transmitters are storied where? What are their actions post depolarisations?

Answer 22

Attached to an asctin web in the terminal; when an action potential arrives at the terminal it causes an influx of Ca+2; docked vesicles then fuse with the membrane releasing there neurotransmitters into the cleft; empty vesicles are then recycled and refiled; the actin web breaks down and new vesicles move to dock

Question 23

Slow release neurotransmitters are located where? What are their actions post depolarisations?

Answer 23

Slow release transmitters are not located on the cell membrane; Trains of action potentials are required o mover them to the membrane before contents can be released

Question 24

Describe kiss and run; what transmitters utilise this system?

Answer 24

Synaptic vesicles merge with the cell membrane but do not fully discharge their contents into the cleft; the vesicle then is re-filled with the neurotransmitters that where lost; slow release

Question 25

what are the two common receptor actions?

Answer 25

Ion fluxes; second-messenger cascades

Question 26

contrast hormone receptors and neurotransmitter receptors

Answer 26

Hormones are slow release they affect receptors at long range and they have very high affinity for the hormone; Neurotransmitters are fast released they affect receptors at a very short range and they have lower affinity for the neurotransmitter

Question 27

most G-coupled receptors are composed of how may proteins; how many transmembrane domains?

Answer 27

single proteins with 7 transmembrane domains; multi-protein complexes each subunit has 4 transmembrane domains

Question 28

most ion gated channel receptors are composed of how may proteins; how many transmembrane domains?

Answer 28

multi-protein complexes in which each subunit has 4 transmembrane domains

Question 29

in the resting state an ion channel is what?

Answer 29

Closed

Question 30

When activated the ion channel receptor undergoes what? This allows?

Answer 30

A conformation change; allows ions to flow into the cell

Question 31

what do cations and anions do to the cell? Give example of both

Answer 31

Cations (K / Na/ Ca) depolarize the cell; Anions (Cl) hyperpolarize

Question 32

at the Neuromuscular junction what receptor is activated?

Answer 32

Nicotinic acetylcholine receptor

Question 33

at the Neuromuscular junction What neurotransmitter is used? what degrades this neurotransmitter?

Answer 33

Acetylcholine; acetylcholinesterase;

Question 34

On a Ligand-Gated Ion Channel there are how many binding sites? These can bind?

Answer 34

multiple binding sites; can bind agonists or modulators

Question 35

describe the mechanism of activating a g-protein linked receptor

Answer 35

agonis activation -> conformation change -> alter second-messenger -> turn over in the cell

Question 36

there are _______ receptors for each neurotransmitter?

Answer 36

Multiple

Question 37

neurotransmitter transporters are all Coupled with? Glutamate’s transporter is also coupled with?

Answer 37

GABA glycine dopamine noradrenaline and serotonin transports are also coupled with?

Question 38

Neurotransmitter transporters are driven by?

Answer 38

ionic gradients