Neurotransmitters and membrane channels

Question 1

Define neurotransmitters

Answer 1

Neurotransmitters are chemical substances produced in different parts of the central nervous
system; once liberated in the synaptic cleft, they bind to specific receptors and modify the
potential of the postsynaptic membrane.

Question 2

Classification of neurotransmitters depending on the place of formation

Answer 2

-Classical neurotransmitters: which are amino acids or derivatives; they are synthesized
from blood precursors which are transported with their synthesis enzymes produced in
the cell body, through the axon, toward the synaptic bud where their synthesis and
storage in the synaptic vesicles will take place.

-Neuropeptides: are composed of many amino acids; their precursors are synthesized
in the cell body in the same time as their conversion enzymes and then transported
through the axon toward the synaptic bud where they are converted into
neuropeptides and stored in synaptic vesicles.

Question 3

Classification of neurotransmitters depending on their molecular structure

Answer 3

• Classical neurotransmitters: they may be amino acids (Glutamate, Glycine) or
  derivatives (GABA, Dopamine, Noradrenalin) or carbohydrates derivatives
  (Acetylcholine).
• Neuropeptides: they are composed of many amino acids (substance P,
  enkephalins) ,

Question 4

Classification of neurotransmitters depending on their functions

Answer 4

-Excitatory: acetylcholine is excitatory, when its receptors are Na + channels and
inhibitory when its receptors are K + channels.
- Inhibitory: GABA and Glycine are inhibitory because their receptors are Cl - channels.

Question 5

Classification of neurotransmitters according to their speed

Answer 5

-Ionotropic: (acetylcholine, GABA, adrenaline) they bind directly to the receptors. The
message is fast.

• Metabotropic: (dopamine, noradrenalin) bind to receptors coupled to enzymes allowing
  the synthesis of secondary messengers whose action will modify the membrane
  permeability, so their action needs a certain time.

Question 6

If ACH excites the skeletal muscle, then…

Answer 6

then ACH has an excitatory role

Question 7

If ACH inhibits the cardiac muscle, then…

Answer 7

the ACH has an inhibitory role

Question 8

If Noradrenaline accelerates heartbeat, then…

Answer 8

then noradrenaline excites the body

Question 9

If Noradrenaline facilitates wakefulness

Answer 9

then noradrenaline maintains wakefulness

Question 10

If Noradrenaline excites hyper feeling

Answer 10

then noradrenaline regulates the mood

Question 11

If Dopamine increases motions & reactions, then…

Answer 11

then dopamine controls complex movements

Question 12

If Dopamine increases pleasure

Answer 12

then Dopamine is responsible for pleasure sensation

Question 13

If Serotonin increases/ decreases temp.

Answer 13

then Serotonin regulates body temperature

Question 14

If Serotonin induces sleep process

Answer 14

then it controls the sleep situation

Question 15

If Serotonin facilitates pleasure

Answer 15

then it plays a role in pleasure feeling

Question 16

If GABA inhibits the neuron/muscle

Answer 16

then GABA causes relaxation

Question 17

If P-substance causes pain feeling

Answer 17

P-substance has algesic function

Question 18

If Enkaphaline inhibits pain feeling

Answer 18

Enkaphaline has analgesic function