BehaviouralPharmacology Flashcards
Translational biomedical research
research conducted in the area between the bench (labbased experiments), the bedside (clinical research and patient management) and the healthcare
system (broad implementation and health economics) with the aim of improving the prevention,
diagnosis and treatment of disease
Initially mouse models were used for
modelling a disease; e.g. ischemic stroke models
Current animal models
development of “human physiological systems” within the mouse model
opportunities to test both gene and pharmacological therapies
e.g. gene mutations
When using animal models never forget that
knowledge about animal models, attention to the
quality, including validity, specificity, and comprehensiveness, of animal models is a crucial component
of the effectiveness of translational research in behavioral neuroscience
Goal of behavioural pharmacology
develop and refine behavioral procedures effective in helping to screen drug candidates for potential clinical effectiveness
2 type of relationship between subject designs
between and within
Common Dependent Variables
- Arousal level (EEG)
- Sensory measurements (Thresholds & Timing)
- Cognition (Memory & Vigilance / arousal)
Less Common Dependent Variables
-Motor tasks
Motor coordination
Tapping rate
Non humans too
- Timing
- Learning and memory
- Avoidance
- Paw lick test
What is a “model”?
Typically models are preparations in animals that attempt to mimic a human condition
but in general it is any experimental preparation developed for the purpose of studying a condition in the same or different species
2 main purpose of animal models
-Mimic the syndrome in its entirety
Difficult if your knowledge of the syndrome is incomplete and changing
-Study potential therapeutic treatments
Tends to concentrate on effects of known drugs may hamper identification of new drugs with novel mechanisms of action
Animals models can be used to
-Mimic only specific signs and symptoms
Symptoms being modelled may not be diagnostic for the disorder but should be reliably measured and defined
-Mimic the psychological constructs thought to be affected in the disorder
Useful for studies that involve both patients and putative models
Model validation
- Models assume a common basis for the behaviour and physiology of various species
- Models should be reliable in terms of induction and outcome.
- Variability cannot always be considered an error
Predictive Validity
- The ability of the model to predict the human phenomenon. Usually this refers to treatment (pharmacological isomorphism)
- Important criterion since the scientific process requires the testing of predictions
- Predictive validity and reliability may be sufficient to define a good model.
Construct Validity
- The accuracy with which a model measures what it is intended to measure
- Often considered the most important criterion but rarely established
- Ongoing modification of the model as ideas about the disorder evolve
Face Validity
- The model resembles the disease being studied
- Different species may not reflect similar symptoms even if the aetiology of the condition is known
- Similarities between symptoms do not necessarily implicate similar aetiologies
Adverse drug effects (ADE)
- 68% of the ADE’s found experimentally, were also found in humans
- and 79% of possible adverse effects not seen in animal, do not occur in patients
- Approx. 90% of the carcinogenic substances have been shown to have carcinogenic effects in animal experiments
General rule of using animal models
- Don’t anthropomorphise擬人化
- Emotions are personal, internal, and highly species-specific.
- There is no way for a human investigator to know whether a mouse is feeling afraid, anxious, depressed, or experiencing hallucinations.
- observe the behavioural and physiological responses that a mouse makes to stimuli and events.
- The anatomy, physiology, and neurochemistry of the mouse is similar to the human in many aspects
What makes behavioural lab special
- limited number of species
- focus: Behaviour, typical for the majority of individuals
- standardised environment (housing conditions)
- standardised environment (experimental conditions)
Standardise your methods
- quiet working climate
- one experienced person – throughout to reduce variation
- always perform your experiments at the same time of day
- positive conditioning (if possible)
Variables to consider for animal behavioural tests
ANIMAL -species -gender -age -breeding/keeping EXPERIMENTER -education/experience -positions towards animals/expectations -experimental procedure OTHERS -time -season -environmental factor
Environmental factors affecting behaviour
- noise
- lighting
- food
- bedding
- housing
- temperature
-individual abilities/characteristics
Noise
- random, loud, and intermittent noises can disrupt behaviour
- control experiments with background “white noise”
- random noises can result in false startle responses or habituation to startle stimuli
Lighting
- albinos are susceptible to retinal degeneration
- high light levels can be anxiogenic
- random changing of high and low light levels will have effects on behavioural assays
Housing/bedding
- group housing vs. individual housing (hierarchies develop especially in mice)
- changes in bedding can be stressful
- is bedding edible?
- do bedding particles get stuck in behavior equipment?
Strain
Different strains of rats and mice have different behaviours
Supplier
- The same strain from different suppliers have different behavioural effects
- The same strain from the same supplier, but from different sites may differ in behaviour
- Consider shipping conditions
General behaviour: Neuroscore
- behavioural observation in the home cage
- transfer to an open arena (38 x 59 cm, Cage type IV)
- observations during the transfer on the palm
- total of 13 observational topics
- duration: about 2-3 min per mouse
Rules:
- the observer is blinded
- always at the same time of day
- the test procedure should not vary
- only the general deficits and then detect the focal-related deficits
- if human endpoints are reached, then euthanasia
IG: Neuroscore parameter
Parameter:
- grooming / piloerection
- ears / response to noise
- eye
- posture
- spontaneous activity
- symmetry axis of the body
- gait
- climbing (45 ° upward)
- spontaneous circling
- symmetry of forelegs
- forced circling
- whiskers sensitivity
- grip-test of the forepaws
Tests to check motor functions
Open field Footprint pattern Rota-rod Hangingwire Stereotypy Circadian wheel running
IG: Rota rod
Sensorimotor Test
Training:
animals are placed 3-20 x on the rotating rod
After cerebral ischemia, the animals are placed 3-5 x on the accelerating (4-40 U / min) rod and the time until falling off determined
repeated testing is possible
Parameter:
time on the accelerating rota rod (max 300 s)
maximum speed of the rod
sensitive up to 14 days post-ischemia
IG: Pole test
Sensorimotor Tests
Training:
- min. two days 3-5 times per day in the home cage.
- First already upside down, then head up.
- On testing day, the mouse will be placed with head up on the top of the pole
- time of turning, and the duration of the down climbing (average of 5 tests) is determined.
- The measurement can be repeated.
Parameter:
- Time to turn
- Time to reach the floor
sensitive 14 days post ischemia
IG: Corner Test
Sensorimotor Tests
- no training needed
- a preoperative test may reveal an individual page preference
- postoperatively, the animals are placed for 5-10 minutes in the test arena and the percentage of turns to one side is calculated
- circling without direct entry into a corner is considered as maximum one side preference
- an optional video recording allows the determination of locomotor activity
Parameter:
% of turns to one side
sensitive up to 90 days after ischemia,
CAVE: minimal activity required, frequent repetition leads to habituation
Sensorimotor Tests examples
Rota rod
pole test
corner test
Gait analysis
IG: Cylinder Test
Parameters:
Hand usage.
Left, right, both
IG: Adhesive Removal Test
Parameters:
Contact time
Removal time
IG: Gait analysis
Sensorimotor test
Allows analysis of:
- Temporal and spatial relation of footfall, gait and transition,
- Gait coordination, on a voluntary basis without aversive stimulation
Parameter:
- more than 30 speed-dependent and speed-independent gait-parameter per foot
- sensitive up to 14 days post ischemia
limitations:
-mice are relatively spontaneous: Transition - Exploration (run-stop)
-many parameters are dependent on speed (walk vs. running)
-reduced speed is often a part of the phenotype
older animals are more difficult to train (continuous running)
Morris Water Maze
- laboratory paradigm used to study spatial ability; the Morris water maze is a large tub of milky water; to get out of the water, rats must learn to swim to a slightly submerged (invisible) goal platform
- Rats learn to do this very quickly, even when they are placed in the water at a different position on each trial; they use external room cues to guide them
- It is interesting to look at their search strategies when the platform has been moved to a new location
Examples of Semi-natural Animal Learning Paradigms
ethlogically semi natural meaning the condition is similar to rat's natural environment Y Maze Radial Arm Maze Morris Water Maze Oasis Maze
3 types of morris maze
place version for acquisition
spatial probe for retention
cued version for visual integrity
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IG: Hole Board
Habituation learning Def.: Reduced exploration after repeated exposure to a new environment 2 x 10 min trials Conducted on two consecutive days Parameters: Nose pokes
IG: Passive Avoidance
trial 1
the animals are placed in the mildly aversive brightly lit chamber
Upon entry into the associated, less aversive dark chamber, they receive a short mild foot-shock (0.2 mA) for 1 s
trial 2
24-96 hours later the animals are placed back into the brightly lit chamber. The time to re-entry into the dark chamber, without foot-shock is determined (cut off 180s).
Parameter:
- Re-entry into the dark chamber on trial 2 after foot-shock experience on trial 1
- sensitive up to 30 days post-ischemia,
Disadvantage: negative reinforcement
important:
animals must be spontaneously active
Type of maze for learning & memory
Y maze
Radial Arm Maze
Radial-Arm Maze
- Is used to study foraging behaviour in the laboratory
- Foraging in the wild is complex; the rat must learn where the food is likely to be, but not to immediately revisit a stripped site
- In the radial arm maze rats quickly learn to go directly to the arms that are baited with food each day, but the rarely visit the same arm twice on a given trial
Goal for phenotyping behaviour
Standardising phenotyping protocols so that someone can share and compare phenotype data from mouse genetics centres throughout the world
Limitation of X maze
Different strains are known to have different behavioural patterns
parameters of anxiety-related behaviour in rats
feeding ‚yes or no‘ (percentage of rats feeding)
time until first food intake in the open field
time spent in the middle of the open field
number of rearings
distance travelled
time spent grooming
External factors affecting behaviour
- choosing the ‚right‘ test
- construction of the apparatus
- personality of the experimenter
- preceding stressors for the animals
- housing conditions prior testing
- „handling“ of the animals prior and during testing
- environmental conditions during the test e.g. light
- selection of the animals - species, strain, age, gender
- characteristics and dose of the substance, way of applications
