Exam 1 Flashcards
What is pharmacology?
The study of the actions of drugs and their effects on living organisms.
What is neuropharmacology?
The study of drug-induced changes in the nervous system cell functioning, mood, thinking, and behavior.
Drug actions in the brain and spinal cord.
What is a drug effect?
A drug effect is basically when the drug binds to its receptor in the body. It is the physical changes produced by drug when it binds to the receptor and the alterations to physiological and psychological function.
What are specific drug effects?
Specific drug effects are biological changes based on physical and biochemical interactions of a drug with a target site in living tissue. Basically, what is the drug supposed to do to the body.
What are nonspecific drug effects?
This is the off-target or side effects of a drug that are unintended. Varies from person to person.
What is the difference between specific and nonspecific drug effects?
Specific drug effects is what is supposed to happen to the body when a drug binds. Nonspecific drug effects are side effects of drug expected to happen but different than drugs intended purpose.
The placebo effect is a type of ________ drug effect.
Nonspecific
What are pharmacokinetics?
Pharmacokinetics is what the body does to the drug. This includes the absorption, distribution, metabolism, and excretion of a drug. Also concerned about the bioavailability.
(Katie- ADME)
What is bioavailability?
Bioavailability is the amount of drug in the blood that is free to bind to target sites. A drug with a higher bioavailability has an easier time getting into the brain.
What are the different routes of drug administration?
Oral/rectal, intravenous, intraperitoneal, subcutaneous, intramuscular, and inhalation.
The way your administer a drug determines _______ and ______ of drug reaching target tissues.
Speed and quantity
(T/F) Recreational drugs are typically taken so they have slow onset of action.
False. Recreational drugs are typically done via inhalation or IV for quick effects.
Drugs taken for medical purposes typically have a slow onset of action. Why is that?
Drugs with a slow onset of action will typically last longer in the body meaning their effects will be exerted for longer.
5 quarts of blood leave the heart and circulate through every organ and returns to the heart after about 45 seconds. What does this mean for drug action?
This means that the faster a drug can get into the blood supply, the faster it gets into the brain.
Why is blood in our veins blue and near the surface of the skin?
Veins carry deoxygenated blood back to heart which reflects blue light. (Only heme + O2 combination reflects red light). Veins are near the surface since deoxygenated blood is less important than oxygenated blood.
How do inhaled drugs get to the brain?
When drugs are inhaled, they diffuse rapidly through capillaries of lungs with oxygen. This is because the surface area of the lungs is so large. The drug molecules then hitch a ride to the brain where actions are exerted.
Inhaled drugs will reach the brain in a few seconds.
How do IV given drugs get into the brain?
Drug given intravenously are put directly into the deoxygenated blood stream (veins). This means it will go back to heart and lungs and will go to the brain after that.
How does subQ administration of drugs get into brain?
SubQ admin gets slowly absorbed through the tissue layers until they enter the blood stream and circulate to the brain. These drugs are slowly absorbed because getting out of fatty layers is hard for drugs as fat traps them.
Why is the blood in arteries red? Why can we not see our arteries?
Arteries carry oxygenated blood which is a mix of heme and oxygen. Together, those molecules reflect red light making blood appear red. Arteries are deep beneath the skin because oxygenated blood is so important.
What connects arteries and veins?
Capillaries!
What are the two quickest routes of administration of a drug?
Inhalation and Intravenous
What are recreational drugs taken via inhalation?
Nicotine, THC, crack cocaine, and crystal meth.
How do medications taken orally get into the body?
They are taken and then enter the stomach that is very acidic. If a drug makes it past that, it will be absorbed by the GIT and taken to the liver. Once in the liver, it goes through 1st pass metabolism. Once spit out by the liver, drug can enter blood stream and bind accordingly.
What are the pros and cons of oral drug administration?
Benefits include being safe, self-administered, and cheap
Cons include degradation by stomach acid and enzymes and 1st pass metabolism.
What is 1st pass metabolism?
This is the chemical alteration of a drug by the liver.
What drug administration techniques avoid 1st pass metabolism?
Inhalation, intravenous, and rectal admin. Technically, intramuscular and sub Q also avoid first pass metabolism.
Evolutionarily, why was 1st pass metabolism developed?
1st pass metabolism helped prevent toxins from entering directly into the blood and killing. Liver could break down active metabolites before entering blood stream preventing death.
What is absorption?
Absorption is the movement of a drug from site of administration to the blood circulation.
What factors effect oral absorption?
Drugs taken orally are absorbed through the GIT tract from stomach to SI. Everything in the GIT has to compete to get through the walls. Influential factors include food already in stomach, type of food, physical activity, and metabolism.
How does a drug injected intramuscularly get into blood stream?
Drugs injected into muscle go towards the arterial supply for the muscle and can enter blood stream from there.
To get a drug to the brain, it must be very _____________.
Lipophilic!
What are the pros and cons of intravenous drug administration?
Pros include quickness and accuracy.
Cons include such rapid onset that little time for overdose help and drug cannot be removed from the body.
Explain intranasal drug administration.
Intranasal drug admin has local and systemic effects. Local effects would include relieving nasal congestion but systemic effects would be overall allergy relief. Can be negative or positive effects. Drugs are fully absorbed within 15 minutes.
Explain rectal drug administration. (Butt chugging)
Drugs given in rectum bypass 1st pass metabolism and reach the brain in a few minutes. Typically given to infants or those not able to swallow.
What is one factor that determines plasma drug levels?
The rate of passage through cell membranes.
How many cell layers does it have to pass through? Can it just diffuse through or does it need a transporter?
(T/F) The plasma membrane of the cell has two hydrophilic heads facing outwards and 2 hydrophobic tails facing inwards.
True!
How do lipid soluble drugs get passed into a cell?
Lipid soluble (lipophilic) drugs can passively diffuse through the plasma membrane to enter the cell.
(FYI- passive diffusion is from high to low concentration gradient requiring no energy)
What is the blood-brain barrier?
The blood-brain barrier is a protective coating covering the blood supply that feeds the brain and spinal cord. It prevents toxins from entering the master organ.
How do drugs in regular capillaries throughout the body permeate different organs?
The drug floating in the bloodstream can leave circulation by passing through gaps in the capillaries. These are specific gaps that allow for leakage.
How do drugs pass into blood-brain barrier and reach the master organs?
Capillaries in the brain have plugs in their capillary gaps meaning drugs cannot leave circulation easily to get into CNS. Only lipid-soluble substances can leave the capillaries here and enter CNS. Very tiny molecules can also pass through. Some active transport may be need to move other chemicals in and out of CNS.
What is the one exception to the blood-brain barrier?
The area postrema in the brain has no BBB. This is our nausea and vomiting center. Allows us to sense toxins and get rid of them before they enter brain.
Where is the deoxygenated blood supply?
Any of the blue portions.
Which figure demonstrates zero order kinetics?
The graph on the left.
Which drug has greater potency?
Drug A has a greater potency. This is because you need less amount of drug A to exert a bigger effect.
What drug on this chart is the most potent?
Hydromorphone
Which drug on the chart is the most efficacious drug?
Drug A is more efficacious than drug B.
Which part of this action potential chart is when Na+ channels open?
Sodium channels open when threshold is reached for an action potential.
Which graph depicts neuronal inhibition?
The graph on the right depicts neuronal inhibition.
Where on the action potential graph do K+ channels open to repolarize the neuronal membrane?
K+ channels open at the very top of the hill.
Which portion of the spinal cord is inhibited by morphine and other opiates?
What is first order kinetics of drug metabolism?
This is the constant drug clearance from the blood in the liver. Rate of clearance os dependent on the concentration of the drug. With less and less drug in the system being metabolized, less liver enzymes need to be activated.
What is zero-order kinetics in the terms of drug metabolism?
This is when drug molecules are cleared at a constant rate regardless of blood concentration of the drug. An example of this is alcohol. Alcohol can only be cleared at 10-15 mL/hour.
What is efficacy of a drug?
Efficacy is the maximum desired effect that a drug can produce regardless of dose.
What is potency of the a drug?
Potency is the amount of a drug needed to produce the desired effect.
Which drug has the best efficacy? Which drug is the most potent?
Hydromorphone, morphine, and codeine all have similar efficacies. This is because they produce very similar effects of pain relief regardless of the dose.
Hydromorphone is the most potent. It is the most potent because you need less of the drug to exert the same response.
What is a partial agonist?
A partial agonist binds to the same site as a full agonist and turns on the receptors just not as much as the full agonist.
An example of a partial agonist is Chantix. Chantix is partial agonist for nicotine receptors.
Do competitive antagonists fight agonist potency or efficacy better?
Competitive antagonists decrease agonist POTENCY.
Do non-competitive antagonists work better in reducing potency or efficacy of an agonist?
Non-competitive antagonists are more effective in reducing the efficacy of an agonist.
In regards to an neuronal action potential, what are the resting intracellular and extracellular ion concentrations?
Extracellular- High conc. of Na+, Cl-, and Ca2+. Low conc. of K+
Intracellular- Low conc. of Na+, Cl-, and Ca2+. High conc. of K+. Inside of cell is overall negative.
Describe the steps of an action potential?
- Inside of neuron becomes more positive until threshold potential is reached. (around -55 mV). It becomes more positive because the overall negative charge within the neuron is attracting positive ions via electrical gradient.
- Threshold potential reach causes voltage gated Na+ channels to open and for those to flow into the neuron.
- Na+ rushes into the cell until the membrane potential reaches around +40 mV.
- At +40 mV, the K+ channels open and K+ rushes out of the cell into extracellular space to repolarize the cell back to negative.
- When repolarization hits -55 mV again, the Na+ channels close and stop letting them into the cell.
- K+ channels close at the undershoot period called the refractory period.
What is hyperpolarization?
If Cl- channels are stimulated to open, Cl- enters the cell and results in hyperpolarization which is inhibitory.
What is included in each of the three different brain regions?
Forebrain- cerebral cortex, thalamus (sensory relay), and hypothalamus (regulatory behavior). The forebrain is the newest part of the CNS.
Midbrain- Motor function, vision, and auditory function
Hindbrain- Medulla (essential body functions), pons (sleep and wake functions), cerebellum (movement and motor memory)
What are some basic characteristics of the forebrain?
Forebrain is the newest portion of the CNS. Most recreational drugs target the forebrain. Somatosensory cortex is in the parietal lobe, and motor cortex is very back of frontal lobe. The main component of the forebrain is the diencephalon. The diencephalon is the second little brain of the thalamus and hypothalamus.
Describe the cross-section of the spinal cord.
Back portion of spinal cord carries afferent signals from body back to the brain. Front portion of spinal cord carries efferent signals from brain to the body. 31 total pairs of nerves that go off spinal cord to get to peripheral areas. The dorsal roots are sensory while the ventral roots are for motor.
What are the 3 main types of neuronal interaction in the CNS?
A. Axodendritic- axon goes to the dendrite. MOST COMMON!
B. Axosomatic- Axon sitting on the cell body/soma of neuron.
C. Axoaxonic- Axon of one cell onto the axon of another cell- cell 1 can regulate how much activity seen in cell 2 which together effect cell 3.
Describe axoaxonic signalling.
Axoaxonic synapses can either reduce or enhance release of a neurotransmitter. If it reduces the NT, it is presynaptic inhibition. If it enhances NT release, it is presynaptic facilitation.
Describe alcohol and GABA release in terms of heteroreceptors.
Under normal conditions, GABA is released from smaller neuron to prevent dopamine release from the bigger neuron. Under conditions of alcohol intake, alcohol causes the small neuron to release an inhibitory neurotransmitter instead of GABA. That inhibitory neurotransmitter causes dopamine to be released by the big neuron and stimulates reward pathways. Alcohol removes the millisecond to millisecond inhibition that GABA produces. Alcohol is a depressant in all pathways except the reward pathway.
Describe autoreceptors.
These are receptors for the same neurotransmitter released by the actual neuron. Helps to regulate how much NT has been released and when to stop releasing more.
What are the two categories of neurotransmitter receptors?
A. Ionotropic- NT binds and allows for ions to flow inside of neuron. Very fast response. Some can change responses via 2nd messengers like cGMP and cAMP.
B. Metabotropic- Larger and thicker proteins that have outside space for NT to bind and an intracellular side attached to a G protein.
