A5 Pharmacology

Question 1

What are the 2 things neurotransmitters can generate?

Answer 1

1. Excitatory post-synaptic potentials (depolarisation: Na+ rushes in)
2. Inhibitory post-synaptic potentials (hyperpolarisation: Cl- comes in)

Question 2

What is summation?

Answer 2

the combination of graded potentials

Question 3

What do slow-acting neurotransmitters do?

Answer 3

They modulate synaptic transmissions in the brain:
triggers second messenger pathways, which trigger ion channels in post-synaptic cell to stay open for longer, so the depolarisation is greater, so it’s stronger too

Question 4

Give examples of slow-acting neurotransmitters?

Answer 4

Dopamine, Serotonin, Acetylcholine, Noradrenaline

Question 5

How do slow-acting neutrotransmitters cause changes of neurons when memory is formed?

Answer 5

The second messengers (triggered by the slow-acting neurotransmitters) promote cellular changes, such as:
- more dendritic receptors in post-synaptic neurons
- more neurotransmitters

So this long-term potentiation makes those neuropathways easier to stimulate

Question 6

How do psychoactive drugs affect the brain (broadly)?

Answer 6

they increase or decrease postsynaptic transmission

Question 7

stimulant drugs mimic…

Answer 7

the effect of the sympathetic nervous system

Question 8

What does cocaine do? Is it a stimulant or a sedative?

Answer 8

Stimulant
- attaches to dopamine pumps on pre-synaptic membrane
- thus dopamine does not get re-uptaken and stays in the synaptic cleft
- causes constant stimulation of post-synaptic neuron

Question 9

What does ecstasy (MDMA) do? Is it a stimulant or a sedative?

Answer 9

• increases activity of neurotransmitters dopamine and serotonin by binding to reuptake pumps
• it increases the release and decreases the reuptake -> overstimulation
• chronic use can permanently damage dopamine system
• longer lasting effects than cocaine

Question 10

What does benzodiazepine do? Is it a stimulant or a sedative?

Answer 10

Sedative
- bind to GABA receptors on post-synaptic neuron
- increases efficiency of GABA action: lets Cl- into neuron, causing hyperpolarisation
- promotes sleep-inducing and muscle relaxing responses in the body

Question 11

What does THC (cannabis) do? Is it a stimulant or a sedative?

Answer 11

Sedative
- binds to cannabinoid receptor on pre-synaptic neuron
- blocks release of inhibitory neurotransmitters , which would prevent dopamine secretion
- by preventing the inhibition of dopamine secretion, the user feels euphoria

Question 12

How do general anesthetics work?

Answer 12

chemicals block Ca from triggering neurotransmitters

Question 13

How does local anesthesia work?

Answer 13

chemicals block Na+ from going into neuron

Question 14

What do neonicotinoid pesticides do?

Answer 14

They mimic the effect of acetylcholine (a neurotransmitter) but unlike acetylcholine, neonicotinoid can’t be broken down by an enzyme, so it overstimulates the post synaptic neuron. This causes paralysis in insects but does not affect humans that strongly because they have weaker acetylcholine receptors.

Question 15

How do endorphins act as painkillers?

Answer 15

endorphins bind to opiate receptors, which inhibit the release of neurotransmitters, so the transmission of pain signals is stopped.

Question 16

Difference between endorphins and anesthesia?

Answer 16

Anesthesia blocks all sensory perception from that area, whereas endorphins only block pain.

Question 17

What can affect addiction?

Answer 17

Genetic predisposition, social environment, after an excessive use of substances, the dopamine receptors will be down-regulated, requiring you to take more.