Lecture 16: Performing Enhancing Drugs Flashcards
What is used for the treatment of ADHD?
Methylphenidate
What is used for narcolepsy?
Modafinil
What is the constitute of cigarettes?
Nicotine
What does nicotine affect?
The cholinergic system
What is nicotine?
ACH agonist
What does nicotine stimulate?
ACH receptors which are ionotropic receptors
What can the administration of nicotine improve?
Performance
Who are more sensitive to the effects of nicotine?
Smokers
Is the mean reaction time quicker or slower for smokers or non smokers
Smokers
In what terms does nicotine have a cognitive enhancing function?
Visual information processing Reaction time
Where was the performance study done?
Radical arm maze
What is the radial arm maze?
Set of runways that all radiate out from the central point
In term of the radial arm maze, what is found to be an improved cognitive performance?
Making less repeated arm entries
What does the administration of nicotine allow animal to do?
Remember where it has been > improved cognitive performance (spatial working memory)
In a specific region of the brain there is a confirmation of nicotinic ACH receptors, what are they referred to as?
Alpha-beta composition
Where does nicotine have an effect upon?
Hippocampus (spatial memory)
What happens when nicotine stimulates receptors within hippocampus and other brain regions?
Bring positive modulatory effects in terms of how the animal performs on anything that depends on its spatial awareness and spatial memory
In how many modalities does nicotine have cognitive enhancing abilities?
One
What is working memory?
Processing information in short term
What Brain region is important in looking at working memory?
Prefrontal cortex
Where is prefrontal cortex locates?
Front of the brain in the medial regions where there is a split between two hemispheres
What does methylphenidate improve?
Short term working memory Long term delayed working memory
What is the role of functional imaging (Fmri)?
Someone performs a cognitive task within mri scanner - detect regions of brain that become most active
What are the cognitive enhancing effect prevented by?
Alpha 2 or D1 receptor antagonist
Where do you get more information from?
Experimental studies where you get local administration with ritlan into brain regions
What does methylphenidate block and how is this demonstrated?
Blocks re-uptake of catecholamine (dopamine and noradrenaline) - in vivo micro dialysis
What does methylphenidate increase?
PFC levels of both dopamine and noradrenaline
What is in-Vivo micro dialysis?
Discrete sampling from brain regions of levels of neutrotransmitters
How does in vivo micro dialysis work ?
Place a dialysis probe into a brain region of interest Perfume dialysis probe with artificial CSF (saline) - this goes through dialysis probe which at its tip have dialysis membrane (free diffusion if many substances including neurotransmitter) Any neutrotransmtter released down into brain down concentration gradient into probe Collect the perfusate and assay it to determine the levels of neurotransmitter of interest
In the prefrontal cortex (PFC) what do you have an increase of?
Dopamine and noradrenaline
What does the D1 receptor activation reduce ?
Noise through CAMP mediated ion channel effect
What does increasing levels of noradrenaline stimulate?
Alpha 2A receptor - enhances signal
What does modafinil improve?
Pattern recognition Digit span recall Mental arithmetic Spatial memory Attention Planning
What are the effects on cognition Influenced by?
Motivation Level of arousal Task difficulty
What is the effect of Modafinil dependent upon?
Baseline performance (reports of decreased performance with high base line)
Action of modafinil
Involvement of catecholaminergic systems
What was suggested that modafinil inhibits?
Dopamine transporter
What are the potential substrates for the action of modafinil?
Histamine Orexin ACH 5-HT Glutamate Dopamine GABA
What does modafinil influence
LTP which is a key phenomen in memory processing
Where does modafinil have strength on?
Synapses
What is modafinil less likely to induce ?
Reported Anxiogenic effects
What lower incidence do you have with modafinil ?
Cardiovascular system effects
What can you get with u-shaped effect?
Memory impairment
What are the side effects of modafinil?
Effect on sleep and wakefulness - affects long term potentiation May unpair working memory in developing brain at clinically relevant doses Abuse potential much lower than psychostimulants Lack of reported anxiogenic effects Lower incidence of cardiovascular system effects
What are the side effects of methylphenidate?
Abuse potential Alteration of circadian rhythms Anxiogenic Memory impairment Increased liability for OCD, additive behaviours, loss of cognitive flexibility
