depressants

depressants

drugs that diminish physiological activity and cortical arousal

sedative

anything with a calming effect

tranquilizer

major/minor. refers to potency level

GABA

biggest inhibitory neurotransmitter in the CNS. most depressants enhance directly or indirectly

GABA-a receptor

ionotropic receptor. 2 GABA binding sites must bind to open the channel. Cl- flows in resulting in hyperpolarization

sedative hypnotics

subclass of depressants referring to barbiturates, benzos, z-drugs and non-barb sed. hyps

barbiturates effects

therapeutic: sedation, sleep anticonvulsant, anaesthesia

other: cognitive/motor impairment, euphoria, respiratory depression, nausea

barbiturates mechanism of action

bind to a specific site on the GABA-a receptor, increase duration of chloride channel opening. result in hyperpolarization and CNS depression (dose-dependent)

barbiturates withdrawal symptoms

anxiety, muscle weakness, abdominal pain, sometimes seizures

first benzodiazepine

librium. 1960

most commonly perscribed benzo now

Xanax and Klonopin

benzo mechanism of action

bind to a specific site on the GABA-a receptor and enhance binding of GABA→ increasing frequency of channel opening. in the absence of GABA they have no effect

benzo withdrawal symptoms

depression, anxiety, mania, suicidality, convulsions. may last months.

Z drugs

non-benzodiazepine hypnotics. sleep aids. name starts w a z.

GHB

both a recreational drug and an endogenous neurotransmitter.

GHB mechanism of action

co-stored and released with GABA in vesicle.

GHB effects

low dose: dopamine release, excitation and euphoria

high dose: heavy sedation, unconsciousness

narrowed window between the 2

alcohol

most widely used depressant and second most widely used psychoactive drug

ethanol

beverage alcohol

methanol

industrial solvent. acts as a toxin for the optic nerve. must be filtered out.

fermentation

how alcohol is created. uses interaction between yeast cells and some type of starch (sugar). upper alc limit = 15%

distillation

method that separates alcohol from its fermented mixture. mixture is heated and concentrated alcohol evaporates and is collected through tubes.

18th amendment

prohibition. banned manufacture, sale and transport of alcohol.

21st amendment

repealed prohibition. only US amendment to ever be overturned

alcohol absorption

through GI tract: 20% stomach, 80% small intestine.

BAC

g of ethanol per 100ml of blood

alcohol metabolism

broken down by alc dehydrogenase to acetic acid and acetate and eventually form water and CO2

alcohol elimination

90-95% metabolized in liver. 2-5% excreted unchanged via breath, sweat and urine. no way to speed up, only time

alcohol harms paradox

lower income folks at the same level of drinking are always at a higher risk (SES factors as a third variable)

prevention paradox

the majority of government costs are from lower→medium drinkers (more of them. pyramid.) more economical to target propaganda to them than offer help to alcoholics

narcotics

legal term used to describe illicit drugs mostly opioids.

natural opioids

eg morphine and codeine. synthesized from poppy sap.

semisynthetic opioids

eg heroin, oxy and dilaudid. synthesized from morphine and codeine.

synthetic opioids

eg fent, methadone. made in a lab

what opioids were used for in ancient history

cough, pain and diarrhea relief

laudanum

common household medicine in the 16th century. opium +alcohol

opioids in the 19th century

freely available in medicines and tonics. often labels didnt properly describe contents

harrison narcotics tax act

first major law regulating opioids. 1914 USA

20th century opioids

synthetic opioids discovered. medical options expanded. recreational use mostly banned (heroin became demonized)

21st century opioids

pharmaceutical companies promoted new opioids (eg oxy) as a safe, effective, long lasting option. pain treated as a 5th vital sign. overprescription lead to a much bigger illicit market

opium act

canada’s first drug law (1908) making it illegal to import, manufacture or sell opium for recreation

opium and drug act

in 1911 the opium act expanded to include recreational morphine and cocaine.

opioid metabolism

in the liver. often produces metabolites that have drug effects (eg heroin and codeine → morphine)

opioid elimination

very dependent on drug. relates to euphoria lvls and addiction potential. eg methadone= biologically active for 24 hrs.

GIRK channels

receptors that reduce metabolic activity within neurons. activated by opioid agonists

mu receptors

in brainstem, spinal cord and limbic system. result in analgesia, euphoria, sedation, respiratory depression and constipation. key in reward pathway.

delta receptors

In forebrain and spinal cord. result in mood modulation, some analgesia and GI effects

kappa receptors

in hypothalamus, spinal cord and limbic system. lead to dysphoria, sedation and reduced dopamine release. counterbalance mu

ORL-1 receptors

similar structure to opioid receptors, but distinct.

naloxone

competitive mu receptor antagonist. Higher receptor affinity than opioids → displaces them. 30-90 minute halflife

endorphins

natural opioid peptides produced in our body. released during pain, stress, excercise, laughter and social bonding. Bind to mu receptors, reduce pain and produce euphoria

opioid withdrawal neurons result

hyperexcitable neuron adaptation persists, resulting in anxiety, pain, dysphoria and flu like symptoms.