topic 4 - stimulants and alcohol

Question 1

intake of cocaine

Answer 1

• snorted or smoked
• reaches peak in blood at 30-60 mins
• easily penetrates blood-brain barrier
• bio half life = 30-90 mins

Question 2

what are the short-term effects of cocaine

Answer 2

• increases in euphoria, energy, confidence, talkativeness, activity, alertness, attention due to being a stimulant

Question 3

what is the action of cocaine at mono-aminergic synapses

Answer 3

• vesicles containing neurotransmitters travel to presynaptic terminal
• once here release NTs into synapse cleft
• auto receptors on presynaptic terminal signal when enough NT has been released
• reuptake channels take NT back from synaptic cleft and recycles
• these channels are blocked by cocaine meaning NT stay in synaptic cleft longer
• autoreceptors bind to NTs and signal to the presynaptic terminal to reduce release of NTs
• reuptake channels pump the back into the presynaptic terminal recycling the neurotransmitter and clears it from the cleft

Question 4

what are the long term effects of cocaine 1

Answer 4

• depletion of monoamines (serotonin and noradrenaline) due to lack of reuptake
• causes crash into depression after several hours
• remedied by taking more cocaine leading to 2-3 day cocaine binges

Question 5

long term effect of cocaine 2

Answer 5

• destruction of nasal septum
• schizophrenia-like symptoms: hallucinations, delusions of persecution, mood disturbances, repetitive behaviours
• sexual dysfunction

Question 6

addictiveness of cocaine

Answer 6

• direct effect on dopamine in the N.accumbens and prefrontal cortex
• large amount of dopamine isnt released however stays around longer so appears this way
• directly activates seeking or reward pathway / dopamine is the addiction

Question 7

amphetamines

Answer 7

speed = orally
crystal meth = smoked
ecstasy = orally
mephedrone = snorted/orally
uptake/half life depend on drug and method of taking
can cross blood brain barrier

Question 8

what are the short term effects of amphetamines

Answer 8

increases in euphoria, energy, confidence, talkativeness, activity, alertness, attention
increases in dehydration, exhaustion, muscle breakdown, overheating, convulsions

Question 9

describe the action of amphetamines at mono-aminergic synapses

Answer 9

amphetamines push neurotransmitters out of reuptake inhibitors. this means that an action potential isnt needed to begin the process of vesicles travelling to the presynaptic terminals

Question 10

ritalin

Answer 10

• acts similarly to cocaine by blocking mono-amine re-uptake transporter
• release more gradual and effect not immediate
• effective treatment for ADHD

Question 11

caffeine

Answer 11

• ingested in coffee or soft drinks
• conc peaks after 40 mins
• easily passes through blood-brain barrier
• half-life = 3.5 to 5 hours

Question 12

what are the short term effects of caffeine

Answer 12

increases alertness and wakefulness
induces clear thinking
induces restlessness
difficulty with fine movement
increases cardiac contractions
constricts blood vessels

Question 13

what are some side effects of caffeine

Answer 13

anxiety
insomnia
change in mood
hypertension

Question 14

what is the physiological action of caffeine?

Answer 14

caffeine blocks adenosine receptors. Adenosine is involved in inducing sleep and vasodilation. by blocking this caffeine stimulates adrenaline release from adrenal medulla

Question 15

what are the long term effects of caffeine

Answer 15

mostly sleep deprivation
countered by using more caffeine to wake up in the morning

Question 16

addictiveness of caffeine

Answer 16

physical dependence which causes withdrawal symptoms
headaches
sleepiness
irritability
difficulty concentrating
psychological dependence includes release of dopamine in n.Accumbens

Question 17

action of nicotine

Answer 17

7 seconds of a puff 25% of nicotine has crossed blood-brain barrier
half life of 2 hrs in chronic smoker

Question 18

short term effects of nicotine

Answer 18

inducing vomiting
reduces muscle tone
reduces weight gain
increases heart rate and blood pressure

Question 19

physiological action of nicotine

Answer 19

binds to nicotinic acetylcholine receptors
nicotinic receptors involved in stimulation of SNS including release of adrenaline from adrenal gland
nicotinic receptors found in the brain
stimulates PNS and SNS with a stronger activation to the SNS which consequently overpowers the PNS

Question 20

what are the long term effects of nicotine

Answer 20

body develops tolerance
wears out heart quicker
major problems from other components of tobacco
unsure specific effects of nicotine

Question 22

action of alcohol

Answer 22

reaches max. blood conc. in 30-90 mins
easily crosses the blood brain barrier - soluble in both water and lipids

Question 23

short term effects of alcohol

Answer 23

low dosage = mild euphoria, lowers anxiety
high dosage = slower reflexes, incoordination, sedation, memory problems
- dilation of blood vessels = heat loss however feels warm due to blood being closer to the skin, however cooling blood through skin then cools core temp
- diuretic - more urination

Question 24

what is the physiological action of alcohol?

Answer 24

• agonist of GABA-A receptors - increases inhibitory processes
• antagonist of NMDA receptor - suppresses excitatory processes - involved in memory formation in hippocampus

Question 25

alcohol long term effects

Answer 25

cirrhosis of the liver brain damage - hippocampus = korsakoff's syndrome foetal alcohol syndrome

Question 26

alcohol addictiveness

Answer 26

physical dependence = tolerance induced even from one night drinking and results in mild withdrawal symptoms. after chronic use, there are very strong withdrawal symptoms - delirium tremens - which can be fatal psychological dependence = it increases dopamine release in the n.accumbens - similar to other NMDA receptor antagonists, strong heritable component to alcoholism