Opioids

Question 1

What are opiates?

Answer 1

Drugs derived from poppy opium

Question 2

What are opioids?

Answer 2

Drugs that work in a similar way to opiates but are not directly derived from poppy opium

Question 3

What are the three classes of opioids?

Answer 3

Natural, semi-synthetic and synthetic

Question 4

Comment on the acute efficacy of opioids

Answer 4

Highly efficacious and with few side-effects

Question 5

Which opioid characteristic is linked to dependency?

Answer 5

The higher efficacy, the more likely to cause dependency

Question 6

Do opioid receptors show stereoselectivity?

Answer 6

Yes. Levorphanol and dextromethorphan are examples

Question 7

Where in the body are most opioid receptors found?

Answer 7

In the CNS

Question 8

Are opioid receptors metabotropic or ionotropic?

Answer 8

GPCR metabotropic

Question 9

What is the mu-type receptor positively and negatively coupled to?

Answer 9

An opioid receptor that when activated results in K+ channels being opened.

Question 10

What differentiates mu, kappa and delta opioid receptors?

Answer 10

They have different pharmacology and are expressed differently in different neuronal regions

Question 11

What is a non-selective opioid antagonist?

Answer 11

Naloxone

Question 12

Name is a pure opioid agonist?

Answer 12

Levorphanol

Question 13

What form do endogenous opioid ligands take?

Answer 13

Peptides

Question 14

Name the three primary endogenous opioid ligands

Answer 14

1) Met and Leu enkephalins
2) Dynorphin
3) Endorphin

Question 15

Morphine most similarly resembles which endogenous ligand?

Answer 15

Met enkephalin

Question 16

What do endogenous ligands act to do?

Answer 16

Reduce neurotransmission on the presynaptic membrane in central pathways

Question 17

Where do endogenous opioid ligands act to produce analgesic effects?

Answer 17

Neurotransmission at the dorsal horn

Question 18

What are some other effects of opioids?

Answer 18

Anti-tussive properties, hyposensitivity of primary CO2 respiratory centre, Induce histamine release, depressed spinal reflex, miosis, reduced gastric motility

Question 19

Side effects are driven predominantly by which receptor?`

Answer 19

Mu-type opioid receptor

Question 20

What is opioid tolerance?

Answer 20

The more frequently opioids are taken, the greater the dose required to produce the same effect due to physiological desensitisation

Question 21

How does overdose occur with regard to tolerance?

Answer 21

When the dose required to produce a response is greater than the lethal dose

Question 22

What is dispositional tolerance

Answer 22

Pharmacokinetic tolerance refers to a reduction of drug reaching the target

Question 23

What is direct tolerance?

Answer 23

Direct pharmacodynamic tolerance refers to a reduction in target receptors or a reduction in the efficacity of target receptors

Question 24

What is indirect tolerance?

Answer 24

Indirect pharmacodynamic tolerance refers to a reduction in downstream targets and how efficacious the intracellular messengers are

Question 25

What is the difference between drug-induced dependence and addiction?

Answer 25

Dependence is the physiological dependence whereby withdrawal may result in serious physical effects on the body. Addiction, however, is a behavioural dependence

Question 26

Which neural pathway must be present for the reward effects to take place?

Answer 26

The mesolimbic pathway MUST be present.