3.1.2 The Effect Of Drugs On Neurotransmission

Question 1

What is the agonist?

Answer 1

Mimics the effect of NT, they bind to receptors to excite the neuron, so it seems more of the natural NT is released, increasing action potentials.

Question 2

What is the antagonist?

Answer 2

Reduces the effect or stops the effect of NT, binds to the receptors to block them to stop the message from being passed on or to slow it down.

Question 3

What is the reuptake inhibitor?

Answer 3

Blocks the reuptake of the NT, so more NT stays in the synapse in creasing its action.

Question 4

What does heroin do to neurotransmission?

Answer 4

Heroin binds to the presynaptic neurons that use dopamine as a neurotransmitter.
It changes the action of dopamine in the reward pathway of the brain, releasing more dopamine than usual.
The morphine binds to receptors to reduce the inhibitory effect of GABA on dopamine neurones (those that release dopamine).
The result is more dopamine activity and increased release of dopamine into the synaptic cleft. If the dopaminergic reward pathway continues to be stimulated, this leads to feelings of euphoria.

Question 5

Why are higher doses of heroin needed?

Answer 5

Over prolonged use the brain adapts to high levels of dopamine and slows down it’s own natural production.