alcohol

Question 1

calculating units and safe levels for week, and units for binge drinking

Answer 1

%alcohol*volume (ml) to find absolute alcohol- 1 unit= 10 ml alcohol

men and women< 14 units/week= low risk

binge drinking> 8 units at one time

Question 2

drinking on full stomach vs empty stomach

Answer 2

full- less gastric emptying as stomach breaking down food, and only a bit of alcohol is absorbed directly from stomach, so little gets to intestine

empty- fast gastric emptying= faster speed of onset as alcohol absorbed much better in intestine than stomach

thus speed of onset depends on gastric emptying

Question 3

metabolism of alcohol

Answer 3

90% broken down, 10% excreted

most of breaking down done by liver- alcohol broken down mostly by alcohol dehydrogenase, some by mixed function oxidase into ACETALALDEHYDE

some broken down by alcohol dehydrogenase in STOMACH

acetaladehyde toxic, so broken down into ACETIC ACID by aldehyde dehydrogenase

Question 4

why do we become tolerant to alcohol

Answer 4

mixed function oxidase upregulated, so liver more efficient at breaking it down

Question 5

what happens when you drink too fast

Answer 5

alcohol spills into systemic circulation, as enzymes are saturated

Question 6

why women more affected by alcohol than men

Answer 6

women have less alcohol dehydrogenase in stomach

also less BODY water than men, so more concentrated

Question 7

why is disulfiram effective for alcoholics

Answer 7

inhibits enzyme in 2nd step= more acetalaldehyde

this is toxic, so makes you feel worse, so if alcoholics have more of this, less likely to drin

Question 8

disulfiram genetic polymorphism

Answer 8

common genetic thing in asians, which have less of aldehyde dehydrogenase= more acetaladehyde= Asian flush+ more nauseous

Question 9

important feature of alcohol

Answer 9

LOW potency as simple molecule, so doesn’t bind to a particular target very well compared to other drugs- thus need a lot more of it t have a similar effect

thus doesn’t have a specific pharmalogical target, and had low affinity/efficacy

Question 10

overall effect of alcohol and what dependent on

Answer 10

DEPRESSANT (slows thing down)

does however depend on degree of CNS excitability, which depends on personality, but also environment ie non social or social

if your CNS not very excitable eg due to non-social setting, has more of depressant effect

generally low dose excites CNS ie more confident/excited, high dose leads to alcohols main depressant effect

Question 11

targets of alcohol+ mechanism

Answer 11

GABA receptors- alcohol directly acts on receptor, as well as releasing more allopregnanolone from presynaptic membrane= more GABA

inhibits NMDA receptors (less glutamate) and Ca2+ channels

Question 12

alcohol and euphoria- mechanism

Answer 12

like cannabis, GABA is surpressed, so less inhibition of reward pathway

alcohol acts on opioid receptor like opiates, which supresses GABA

Question 13

effects of alcohol in the brain

Answer 13

corpus callosum- needed for logic/rules

hypothalamus- eating/temp

RAS- consciousness

hippocampus- memory

cerebellum- movement

all impaired as it’s depressant

Question 14

mechanism of cutaneous vasodilation/Asian flush

Answer 14

acetalaldehyde causes less Ca2+ entry and more prostaglandins= less contraction of precapillary sphincters

Question 15

CVS effects of alcohol

Answer 15

depresses baroreceptor activity- baroreceptor switch on when stretched to inhibit SNS/ increase PNS, so leads to TACHYCARDIA

Question 16

endocrine effect of alcohol

Answer 16

diuresis as aldehyde inhibit ADH

Question 17

chronic effects of alcohol on brain

Answer 17

leads to thiamine deficiency, which is needed for energy: brain regions with high energy demand more affected

leads to dementa- cortical atrophy ie confusion, eye problems, problems with gait

leads to WERNICKE-KRSAKOFF syndrome-

Question 18

chronic effects of alcohol on liver

Answer 18

NAD+ needed to break down alcohol: if too much alcohol NAD+ can’t be used for lipid metabolism= fat build up and ketoacidosis

leads to fatty liver acutely (fat droplets), which is acutely reversible

ketoacidosis causes inflammation, which causes reversible hepatitis, which can then lead to cirrhosis (hepatocytes replaced by connective tissue)

Question 19

beneficial effects of alcohol

Answer 19

low dose lowers CVS mortality perhaps due to polyphenols

Question 20

chronic effects of alcohol on stomach

Answer 20

acetaldehyde in stomach can damage gastric mucosa, an may cause stomach cancer

Question 21

chronic effects of alcohol on endocrine system

Answer 21

increases ACTH (cushing like), and decreases testoerone

Question 22

how is hangover caused, and what occurs in hangover

Answer 22

symptoms worst when alcohol conc 0

leads to nausea (vagus affects vomiting centre), headaches due to vasodilation, fatigue due to sleep issues (alcohol causes REBOUND CNS excitation when it’s )