Quiz 1 Flashcards
What is Psychopharmacology?
The study of how drugs interact with the brain and their effects on behaviour.
What legal drug is lethal upon contact in it’s purest form?
Nicotine
Which 2 drugs, 1 legal & 1 illegal, both work identically?
Morphine & heroin
What legal OTC medication can cause life-threatening liver failure when paired with alcohol?
Tylenol
What legal OTC medication shares categorical properties with Ketamine & PCP?
Robotussin
A compound to treat heart problems has been derived from what plant?
Foxglove (causes heart failure as a plant)
T/F: Substances derived from natural sources are safer.
FALSE!
What is a drug?
A non-nutritive substance that is taken into the body and produces a specific change by binding to a receptor or target site.
Interaction between receptor and drugs is called ____
Drug Action
What is alcohol classified as?
Food, it is energy-giving.
Name 1 CNS stimulant
(any of) amphetamine, cocaine, nicotine
Name 1 CNS depressant
(there are many) Alcohol, barbituates
Name 1 analgesic
(opiates of all kinds) morphine, codeine
Name 1 hallucinogen
Mescaline (norepinergic), LSD (synthetic), psilocybin (magic mushrooms)
What is a psychotherapeutic drug?
General category for drugs used to treat mental illness (prozac, thorazine)
What is an example of a semisynthetic form of opium?
(any of) Heroin, hydromorphone, oxycodone, etorphine
What is an example of a synthetic form of opium?
(any of) Pentazocine, meperidine, fentanyl, methadone, LAAM, propoxyphene
What is an example of an endogenous (made within the body) opioid?
Enkephalins, endorphins, dynorphins
How does a drug move through the body (4 steps)?
- Administration
- Absorption/distribution
- Binding
- Metabolism/elimination
What are some common ways to administer drugs?
Oral (p.o.), Rectal/vaginal (suppositories), Inhalation, Oral-nasal mucosal, Topical (creams, etc.), Parenteral injection (outside or around digestive tract), Intravenous (IV), Intramuscular (IM), Subcutaneous, Intraperitoneal, Epidural, Intracerebroventricular (research/surgical use)
T/F: The method of administration has no relation to how absorption or distribution will carry out.
FALSE!
If an individual would like their drug effects to begin rapidly, how/where would they administer?
Closer to left side of heart = faster to brain, inhalation is fastest
What factors influence absorption?
Drug chemistry (solubility/ability to penetrate membranes), First Pass Effect (metabolism/liver), Bound Vs. Free drug, Individual differences in physiology
How might a drug be distributed?
Have to cross at least 1 selective barrier; may have to bind to carrier proteins in blood; May be sequestered in “depots” (not active sites, may be released at a later time); many require conversion to be lipid-soluble
The blood brain barrier’s capillaries:
are almost impermeable, surrounded by astrocytes, require carrier-mediated or lipid-solubility for substances to cross
What is induction (liver)?
Drug makes liver produce more enzymes
What is inhibition (liver)?
Enzyme needed to metabolize drug is blocked
Which family of enzymes all seem to have a role in drug metabolism?
Cytochrome P450
What is biotransformation?
Getting things out of the body. As liver metabolises, drugs turned into water soluble form to pass through Bowman’s capsule and kidneys for excretion
What is a half life?
t1/2 - the time it takes for half of the drug to be distributed or eliminated
What are the two primary mechanisms of drug action?
- Act as neuromodulators
- mimic or block effect of the released transmitter by directly influencing receptors
How does an agonist act?
Mimic or potentiate the actions of neurotransmitters by fitting into the same receptor, potentiating release, blocking reuptake
How does an antagonist act?
Block or decrease action of neurotransmission by b locking a receptor, blocking synthesis, speeding up metabolism
How do we measure the pharmacodynamic action of a drug?
Dose-response relationships
If a dose-response curve is futher right, you need ______ (more/less) drug to achieve desired effect
More
What 3 indices of information does a dose-response curve give us?
- Potency
- Efficacy
- Therapeutic index (drug safety)
What is competitive receptor binding?
Competition for the same binding site as a transmitter
What is non-competitive receptor binding?
Drug binds to site that is not the same as transmitter, effect of drug modulated
In the case of morphine, what does naloxone do?
Causes dose-response curve to shift to the right because naloxone is sitting on receptor. Therefore, more morphine is needed to produce same effect
The green pepper model refers to:
Ionotropic receptors - can affect cell quickly and change membrane potential
T/F: Metabotropic receptors don’t necessarily change membrane potential, they do set off long chain of events
True!
This type of cell is important for the breakdown of glutamate and GABA
Glial
What are some ways a drug targets the synapse?
- can serve as precursor to neurotransmitter (NT)
- can inhibit NT synthesis, depleting levels in whole brain
- prevent storage in vesicles
- stimulate or inhibit release of NT
- stimulate/block postsynaptic receptors
- stimulate auto-receptors (decrease in release)
- block auto-receptors (no feedback to neuron)
- inhibit degradation
- block reuptake
What transmitter system is affected by Deadly Nightshade?
Acetylcholine
Where does acetylcholine come from?
Made endogenously in the liver, derived from diet (part of B vitamin family)
What are some effects of Acetylcholine (ACh)?
- dry mouth
- controls exocrine glands
- works on all body systems in peripheral nervous system
- Run parasympathetic nervous system
- promotes arousal in both sexes
What is the life cycle of ACh in a general cholinergic synapse?
- made in terminal
- packed into vesicles
- classic system of release and reuptake
- not taken back into cell whole, broken into choline and acetate, choline is taken back up
What is included in the monoamine transmitter group?
- Catecholamines: dopamine (DA), norepinephrine (NE), epinephrine (EPI)
- Indoleamines: serotonin, melatonin
How are the catecholamines related?
Through their synthesis, can’t make NE or EPI without DA
Synthesis of NE:
Tyrosine -> DOPA -> DA -> NE
What enzyme is required for NE to become EPI
Phenylethanolamine-N-methyltransferase (PNMT)
Dopamine is responsible for:
Movement and motivation
How does the catecholamine synapse work?
- DOPA (crosses blood-brain barrier) -> DA -> vesicular monamine transporter
- D1, D3, D5 receptors decrease release/firing rate = inhibitory effect
- D2, D4 receptors have enzyme in membrane = still inhibitory
- DA vesicles have active zone-like release sit, can be released all along cell
How does a D2 receptor work?
When DA or D2 agonist enter D2 receptor, activates inhibitory G protein, neg. effect on adenylyl cyclase, inhibitory
How does a D1 receptor work?
When DA or D1 agonist enter, activate excitatory G protein, activates adenylyl cyclase = excitatory
What are some functions of NE?
- widely affect cortex including hippocampus and spinal chord
- controls many aspects of cerebellar function
- involved in arousal
- rest = inhibited activity
- waking up & bringin in sensory stimuli = excited
- major transmitter of sympathetic nervous system (makes you anxious and want to GO!)
NE receptors:
- are metabotropic and occur in two families (alpha and beta)
- are widepsread throughout the brain and other body tissues
- share mechanisms with multiple other transmitters
What is the obligatory precursor of all indoleamines?
Tryptophan
_____ is the rate-limiting enzyme for the synthesis of all indoleamines
Tryptophan hydroxylase
How is serotonin synthesized?
L-Tryptophan -> 5-HTP -> 5-HT (serotonin)
How is tryptophan regulated?
Diet. Tryptophan can pass tghrough blood-brain barrier, but large amino acids (proteins) will compete for access
Where is melatonin made?
Pineal gland
What is the obligatory precursor for melatonin?
Serotonin (5-HT)
You would need to cut out all fermented food when taking a drug that effects this system
Monoamine oxidase (MAO) - metabolises all monoamines
MAO is the sole metabolic enzyme for _____
5-HT (serotonin)
Excitatory amino acid transmitters include:
Glutamate and aspartate
inhibitory amino acid transmitters include:
Gamma-aminobutyric acid (GABA) and glycine
Learning and memory relies on this forward stimulus
Glutamate
T/F: Glutamate is highly neurotoxic and many agonists that are found in nature can produce brain damage
True
Ketamine and PCP act on these receptors:
glutamate
Glutamate synthesis:
Glutamine + H2O + ATP -> Glutamate + NH4 + ADP + PO4(3-)
Where is glutamate synthesized?
In astrocyte, don’t have same properties as neuron so they don’t die
What happens to glutamine in the synapse?
- glutamine enters cell, is immediately transformed into glutamate and released
- lots of variety in ion channel and metabotropic receptors
- excitatory amino acid transporter (EAAT3) clears glujtamate out of synapse
How is GABA made?
Gluatamte + glutamic acid decarboxylase (GAD) -> GABA
The NMDA receptor:
Works only when certain conditions are met:
- will bond with glutamate only if glycine is present
- requires membrane depolarization to move Mg block
- sodium and calcium allowed into cell
