Behavioural Pharmacology Flashcards
(37 cards)
What is pharmacology?
The branch of medicine that deals with the uses, effects, and modes of actions of drugs.
What is pharmacokinetics?
Subfield of pharmacology death with the absorption, distribution, biotransformation and excretion of drugs.
What is pharmacodynamics?
Subfield of pharmacology dealing with the study of the biochemical effects of drugs and their mechanism of action.
What is behavioural pharmacology?
The study of the relationship between the pharmacological actions of drugs and their effects on behaviour and psychological function.
Why not just experiment using humans?
Largely because of more severe ethical limitations, especially when dealing with drug-naive subjects. Don’t know which direction the effect is - could be another reason that causes a change in the frontal cortex, which led them to become an addict. Could be an addict and have changes in the prefrontal cortex, but the two do not have to be related.
What is primary evaluation?
Start with observation of simple “unconditioned” behaviours. Analyse what effect the drug has in terms of locomotor activity, balance, posture, eating and drinking, circadian cycles etc.
What is the rota-rod test?
Test of balance and motor function. Measures the ability too the animal as a function of the drug they’ve taken to maintain their balance.
What are effects of drugs on spontaneous behaviour?
Lyon and Robbins - Looked at measures of sleep, social investment, grooming and feeding relative to amphetamine. Increase dose leads to radical change in how the animal is spontaneously engaged in an activity. Get potent increases in rearing and locomotion - animals become hyperactive. Drugs do not create new behaviours - they alter the probability of behaviours already in the organisms’ repertoire.
What is the tail-flick test?
Place animal on a platform, apply heat source to tail, have a dimmer so can increase the heat source, and measure the time it takes until the animal flicks its tail away. Highly predictive of analgesic effects in humans.
What is the hot plate test?
Place animal on platform and the whole platform is heating up, test how long it takes for the animal to lift its leg. If drug increases the time, this indicates analgesic effects in humans.
What is the elevated plus maze?
A test of anxiety. Measure the amount of time that rodents spend in the bright, exposed maze arms compared to the dark, sheltered maze arms. Highly predictive of anxiolytic efficacy in humans (e.g. benzodiazepines) - increases willingness to explore open arms.
What is the radial arm maze?
Use in a variety of memory tests. Give the animal a problem to figure out to find the food. Give simple task of having to remember what you did a short while ago. Looking at cognitive effects, spatial working memory. See if a drug has a detrimental or positive effect on this.
What is the morris walter maze?
A large round tank of water, in a room with various external cues providing navigation cues. One location where animal can stand. Measure time needed to find the platform, the path length, and the percentage time spent searching at the correct location.
What is drug discrimination?
A method to ‘ask’ animals about the interoceptive cues associated with different drugs. If inject with saline, press left lever to get reward. If inject with cocaine, press right lever to get reward. This shows that the animal is aware of the effect of the drug, as if they press the right lever they feel the effect of cocaine. See similar curve on drug discrimination curve when studying cocaine and amphetamine. Cocaine and amphetamine produces similar psychological and physiological responses, but the difference is that amphetamine lasts much longer. But - drugs are complex (dose, route of administration, individual, etc.)
What are measures of abuse potential?
Comparing drugs via relief of withdrawal symptoms. Steps: produce physical dependence with prototypical drug (e.g. propane), then withdraw (either remove drug or give opioid antagonist to produce withdrawal) and give drug test. IF blocks withdrawal symptoms will probably produce similar dependence syndrome. However, not conclusive, as withdrawal is not conclusively linked to addiction.
How do we examine the reinforcing/incentive
properties of drugs (“will you work for it?”; “do
you ‘want’ it?”)
Conditioned place preference learning
‣ Drug self-administration
‣ Models of relapse
How are drugs reinforcers?
Positive reinforcement: presentation increases the probability of the preceding behaviour.
Negative reinforcement: removal increases the probability of the preceding behaviour. Avoiding something bad (e.g. taking a drug to make you less anxious).
Punishment: presentation decreases the probability of a behaviour.
A single drug can have all three effects at once.
What is conditioned place preference? (CPP)
Two distinct chambers, place animal in chamber one day and give it a drug (e.g. cocaine). Next day put the animal in another environment and get it nothing. If drug has reinforcing effects, the animal will go in the environment where they experienced this. Measuring the memory of the drug rather than the rewarding effect when it is in your system.
What are advantages of CPP?
Fairly simply procedure. Limited effort required (subjects learn preference quickly). Test in non-drug state (avoids ‘side-effects’)
What are disadvantages of CPP?
Not measuring the drug reward itself, but rather the rewarding effects of ‘secondary reward’ (drug-paired context). Psychological and brain mechanisms poorly understood.
What is the skinner box?
When press lever is releases a bit of the drug that is transmitted via n IV. Not just how much they press, but how often - is it out of control or is it in regular intervals? This varies depending on pharmacokinetic factors. Gold standard because drugs that humans and animals will readily self-administer.
What is drug self-administration?
Drugs that maintain self-administration are amphetamines, barbiturates, cocaine, codeine, ethanol, fentanyl, heroin, MDMA, morphine, nicotine, THC etc. Drugs that don’t are aspirin, lidocaine, LSD. One exception where humans self-administer and animals don’t are hallucinogenics. Nearly all drugs that people abuse, animals will self-administer. High predictive validity.
What are ratio schedules of reinforcement?
Fixed Ratio (FR) - reinforcement after every n responses. Majority of studies use this, i.e. reinforcement after every response or for every 5 responses. Variable Ratio (VR) - number of presses required is unpredictable, but varies around some mean. e.g. VR15 = reinforcement on average every 15 responses (e.g. between 10 and 20)
What are interval schedules of reinforcement?
Fixed Interval (FI)- reinforcement given when first press after a fixed delay, e.g. FI-2min - reinforcement for 1st press every 2 min Variable Interval (VI) - reinforcement given when first press after a varying delay around a mean, e.g. VI-4min - reinforcement for 1st press after 4 min on average (e.g. between 4 and 6 min).
