PSYB65 Lecture 8:
Depressants:
- categorized into barbiturates, non-barbiturates, and alcohol
Barbiturates:
- usually used to help people sleep and relax
- work through GABA, primary inhibitory amino acid/neurotransmitter in the brain
- if you increase GABA, slow things down because it is an inhibitory
- barbituates bind to GABA receptors in the brain – decreases the excitability in the
brain
- it is also synergistic with other sedatives/hypnotics – in that they slow down brain
- also synergistic with anxiolytic drugs, like valium, that calm people down,
alcohol, and anti-convulsants (medication to stop seizures by reducing firing
activity in the brain)
- synergistic: if put them together, they are additive/multiply to eachother’s effects
- many old stars died by mixing barbituates and alcohol – which depress the brain
to a point where you never wake up, since they are synergistic
- traditionally used for the elderly – sleep patterns become irregular as you age
- also causes less time in REM sleep, wake up not as rested
- withdrawl: one of the strongest depressants, can have seizures/convulsions (if
took barbiturates for a long time); rather can administer other depressants (like
alcohol), to allow them get through the withdrawl without seizures
Alcohol:
- is a CNS depressants
- produced by yeast digesting sugar and excreting alcohol
- damages society more than any other drug
- alcoholics have largest admissions to mental hospitals – 40% are alcoholics in
mental hospitals
- accounts to 55% of all arrests – 55% individuals had been drinking
- in terms of homicides, alcohol accounts 50 – 75% of all homicides
- 50% of car accident deaths involve alcohol
- 20 – 30% of all suicides, person was drinking
- Prohibition: existed in US from jan 1920 – dec 1933; there was initially a drop in
these alcohol related problems, 10 years later (by 1930), all the numbers were
right back up to where they were before prohibition and other problems were
added due to people consuming impure homemade alcohol (government was no
longer inspecting the alcohol, people would make methyl alcohol rather than ethyl
alcohol)
- Methyl alcohol leads to permanent blindness or death
- Lesson: if people really want a drug, they will get it
- Now, rather try to educate people, so people learn the consequences and negative
effects
- It is absorbed directly through the stomach lining – most other things must be
broken down; very high source of energy – 200 calories per ounce, 7 calories per
gram
- Since it gets through blood stream instantly, it is the fastest source of energy - Cant enter any metabolic pathway where it will get stored as fat
- Causes the brain to decrease ADH (antidiuretic hormone) – causes you to have
more fluid leaving the body than coming in and leads to dehydration
- Works on GABA – but many lines of research suggest that there are multiple
causes – generally slowing metabolic activity in the neuron, or altering membrane
excitability in the membrane
- Effects depend on the dose level – low doses (1/2 drinks) cause disinhibition of
the cortex ( the cortex shifts into an arousal state) by depressing inhibitory centres
in the CNS
- As levels of alc increases, has a direct depressant effect onto the brain (cortex and
cerebellum) - leads to slurring words, staggering, etc
- Can kill you in high doses
- There is a reflex – a blood alcohol level triggers the brain to vomit
- Long term alcohol consumption (high levels for long time – every day) causes
atrophy in the brain, particularly in the dendrites of the cortex and cerebellum –
they shrivel up – can see it in CAT scan
- After withdrawl of high levels, get hallucinations, tremors, convulsions - is as
severe and likely to cause death than people coming of other drugs, like heroin
- Tolerance does develop because the liver creates more liver enzymes to break
down the alcohol when people drink too much
- Alcohol in pregnancy – as mother drinks more and more, the infant when it is
bored will go through withdrawl within 6 to 8 hours of birth
- In high doses, we get fetal alcohol syndr
More
Less
