(5) neural communication II & drug properties (midterm 2)

Question 1

What is the role of serotonin?

Answer 1

• primarily from raphe nuclei (brain stem)
• precursor - tryptophan:
  
  • process to cross bbb requires carbs
• serotonin depletion:
  
  • increased aggression, impulsivity
  • decreased cognitive flexibility
• hallucinogens act on its receptors

Question 2

What is the role of acetylcholine?

Answer 2

• neuromuscular junction
• also basal forebrain: wakefulness, attention, etc.
• nicotine: acetylcholine agonist

Question 3

What is the role of endocannabinoids?

Answer 3

• retrograde transmission: travels from dendrite to axon

- mechanism for forgetting: weaken connection b/w 2 cells at synapse

Question 4

What is the role of adenosine?

Answer 4

• ATP is cellular energy
• adenosine is ATP byproduct
• caffeine/theophylline, adenosine inhibitor
• one of the mechanisms for sleepiness

Question 5

What is the role of endogenous opiods?

Answer 5

• aka Endorphins
• giant peptide NTs
• NT systems that exogenous opioids (e.g. heroin) mimic
• fentanyl & naloxone: opiod receptor antagonists
• all G-protein-coupled receptors:
• found in spinal cord, periacqueductal grey, nucleus accumbens
• pain relief: blocks pain receptors
• causes euphoria

Question 6

What is propranolol?

Answer 6

• norepinephrine receptor antagonist
• beta-blocker
• affects brain & heart
• potential PTSD treatment via reconsolidation:
  
  • reconsolidation: take memory from long term to working
  • decrease emotional response to traumatic event

Question 7

What are SSRIs?

Answer 7

• for depression
• all but 1 are metabotropic receptors
• block serotonin from being removed from synapse, agonist-like effect
• quick effects, slow improvements

efficacy:

- mild-moderate depression: no better than placebo
- major depression: effect size small
    - regression to the mean: unsure if effect is due to SSRI or natural improvement

Question 8

What is the 1st stage of pharmacokinetics?

Answer 8

1. absorption
   
   • drug administration
   • absorbed into bloodstream
   • routes of administration

Question 9

What are routes of administration?

Answer 9

• intravenous: injecting into bloodstream
• intramuscular: injecting into muscles
• subcutaneous: injecting under skin
• per os (by mouth)
• inhalation
• insufflation: “snorting”

Question 10

What are features for each route of administration?

Answer 10

intravenous:
- highest concentration in blood
- broken down most quickly

intermuscular:
- fast, painful, high concentration in blood
- effects slightly longer than intravenous

subcutaneous: not as potent but longer effects

per os: v. long effects, takes long time, lower potency

inhalation: thru lungs
insufflation: absorbed by mucus membranes

Question 11

What is the 2nd stage of pharmacokinetics?

Answer 11

2. distribution
   
   • passage from bloodstream into organs
   • must penetrate membranes

Question 12

What is the 3rd stage of pharmacokinetics?

Answer 12

3. biotransformation

- drug broken down into metabolites by enzymes

Question 13

What is the 4th stage of pharmacokinetics?

Answer 13

4. elimination

- drugs/metabolites or both eliminated from body

Question 14

What might an instrumental/recreational user of a drug want in terms of routes of administration?

Answer 14

instrumental: per os
- looking for long-lasting effects

recreational: intravenous
- looking for strongest effect

Question 15

How does a drug’s acidity relate to its absorption?

Answer 15

drug pKa & environmental pH:

- acidic/basic drug more likely to be absorbed in acidic/basic environment

Question 16

What is bioavailability?

Answer 16

ability for drug to reach its target

Question 17

What factors diminish bioavailability?

Answer 17

• blood-brain barrier
• nonspecific binding
• first-pass metabolism
• active metabolites
• prodrugs

Question 18

What is nonspecific binding?

Answer 18

drugs binds to things other than site of action

Question 19

What are first-pass metabolites?

Answer 19

drug broken down before it reaches site of action

Question 20

What are active metabolites?

Answer 20

metabolites of drug that still have psychoactive effect

Question 21

What are prodrugs?

Answer 21

chemicals that become drugs when metabolised

Question 22

What kind of drugs is able to cross the blood-brain barrier better?

Answer 22

small, uncharged, lipid soluble drugs

Question 23

What effect would active metabolites have on the drug-taking experience?

Answer 23

can increase drug experience

Question 24

How does binding affinity relate to a drug’s effects?

Answer 24

Binding affinity: how strongly drug binds to receptor

• dissociation constant: Ka
  
  • drugs w/ high binding affinity → low Ka
  • drugs w/ weak binding affinity → high Ka

Question 25

How does receptor efficacy relate to a drug’s effects?

Answer 25

Receptor efficacy: how effective drug is at activating receptor
- although drug may bind strongly to receptor, doesn’t mean it is effective at activating it

Question 26

How is tolerance an effect of long-term drug use?

Answer 26

tolerance: need higher dose of drug to get same effect

- regular, everyday use

Question 27

How is sensitisation an effect of long-term drug use?

Answer 27

sensitisation: adaptations appear that make one have increased response to drug
- intermittent use
- stimulant drugs
- effect on behavioural aspects

Question 28

Why might a novel environment be a common component of a story of overdose?

Answer 28

• info from environment helps us prepare for drug use

- interaction b/w cues from environment & drug-taking experience