pharmacology

Question 1

what is the role of Ca2+ in synaptic transmission?

Answer 1

action potential reaches axon terminal and opens voltage-gated Ca2+ channels

higher conc outside so gradient pushes into cell

interact with neurotrasmitter vesicles pushing them towards the membrane (so they can be released into synaptic cleft)

Question 2

what happens to the neurotransmitter in the synaptic cleft?

Answer 2

binds to receptors in postsynaptic neuron :
if ion channels then open when neurotransmitter interacts with them
if not ion channels, interact with specific ion channels and eventually open them

results in post-synaptic potential

Question 3

what are the 3 ways of inactivating a neurotransmitter?

Answer 3

1. diffusion: lost in inter-cellular space
2. enzymatic degradation breaking down neurotransmitter
3. re-uptake: recycled in either neuron (saves synthesis resources)

Question 4

what do substances influence in the synaptic sequence?

Answer 4

1. propagation of action potential
2. release of transmitter
3. modulate how transmitter interacts with post-synaptic receptors
4. modulating inactivation and recylcing

Question 5

example of drug which interferes with signals going through the axon?

Answer 5

TTX - blocks sodium channels in the axon’s membrane

Question 6

example of 2 substances which interefere with release of transmitter and consequences?

Answer 6

tetanospasmin toxin interferes with vesicles of transmitter GABA

reduces amount of gaba released into synapse

imbalance between excitation and inhibition neural signals

strong muscle contractions

also botulinum toxin used in BOTOX by reducing effectiveness of meuromuscular junction in facial muscles

Question 7

example of an excitatory transmitter?

Answer 7

glutamate

Question 8

example of an inhibitory transmitter?

Answer 8

GABA

Question 9

example of mainly excitatory but also inhibitory transmitter?

Answer 9

acetylcholine

dopamine

Question 10

example of neurotransmitters classified by structure?

Answer 10

e.g adrenaline and serotonin known as monamines as contain single amino group

Question 11

example of substance which can enhance the release of transmitter?

Answer 11

amphetamine
enter dopamine releasing neuron through membrane or binding to dopamine transporter

facilitates release of dopamine from vesicles when they fuse to membrane

Question 12

what are thet VTA and nucleus accumbens involved in?

Answer 12

pleasure, reward and motivation

dopaminergic pathways

Question 13

example of substance which can alter how transmitter interacts with receptors?

Answer 13

curare occupies acetylcholine’s receptors in excitatory synapses

blocks them causing paralysis therefore antagonist

used as anaesthetic agent

Question 14

what are antagonists?

Answer 14

blocks receptor at post synaptic cell and prevents neurotrasmitter from binding with it and opening the channels

reduces effects

Question 15

what are agonists?

Answer 15

bind with receptor at post synaptic site but do open the channel hence increasing its effect
(mimics function of e.g heroin mimicing endorphines)

Question 16

what is anandamide involved in?

Answer 16

emotion, pain, appetite and memory

marijuana contains THC which is an agonist of anandamide

Question 17

example of drug influencing transmitter inactivation and recycling?

Answer 17

cocaine blocks the transporter (aiding reuptake into original cell) of noradrenaline and dopamine

interfering with re-uptake and boosting their effect

Question 18

chocolate as a psychoactive substance?

Answer 18

contains small amounts of anandamide and phenylethylamine

in such small amounts that don’t cause noticeable effects

Question 19

coffee as a psychoactive substance?

Answer 19

caffeine competes with adenosine for its receptors

so blocks adenosine and reduces its inhibitory effect

also increases glucose metabolism in cell so increases fuel levels (depeletes sources that already exist)

Question 20

alcohol as a psychoactive substance in low doses?

Answer 20

low doses: agonist of GABA (nhibitory synapses) so increases effect leading to relaxation

stimulates dopamine release which stimulates nucleus accumbens so feelings of pleasure

Question 21

alcohol as a psychoactive substance in moderate doses?

Answer 21

moderate: increases release of endorphines
high: binding to GABA leads to powerful inhibition and sedation

very high: destruction of cell membranes so brain cell death

Question 22

what can anxiety disorders be characterised as?

and how may they be treated in this way?

Answer 22

deficits in GABA-ergic transmission

so benzodiazepines (GABA agonists) reduce anxiety

Question 23

what is a non-competitive and competitive agonist/antagonist?

Answer 23

non- doesn’t bind to same receptor sites as the transmitter

competitive - bind to the same sites in the ion channel as the transmitter

Question 24

what is depression associated with?

and how was it treated in this way?

but problems with treatment?

Answer 24

reduced monoamine transmission (dopamie, serotonin and noradrenaline)

MAO inhibitors as breaks down these monoamines

tricyclic antidepressants inhibit transporter of these monoamines

(both treatments increase levels which effects many other systems so many side effects)

Question 25

what is the current treatment for depression?

Answer 25

serotonin most closely linked monoamine to depression

SSRIs inhibit transporter of serotonin without effecting other neurotransmitters (fewer side effects)

Question 26

what is schizophrenia associated with?

how is it treated?

Answer 26

surplus of dopamine

neuroleptics block transmission of dopamine by binding to dopamine receptors without opening ion channels (dopamine antagonists)

but too little dopamine can lead to parksinsons

Question 27

what does the opposite of neuroleptics?

how?

what are the effects?

Answer 27

cocaine, metamphetamines and amphetamines

reduce transport of monoamine neurotransmitters back into original cell

attach to enzymes which break down neurotransmitters

so boost neurotransmitter transmission (can induce schizophrenia symptoms)