Exam Three Flashcards

Pharmacokinetics

the study of what the body does to a drug

Pharmacodynamics

study of the physiological and biochemical interaction of drug molecules with their target tissue (receptor)

the study of what a drug does to the body

Central Nervous System (CNS)

brain and spinal cord

Peripheral Nervous System (PNS)

sensory nerves, motor nerves, and autonomic nervous system

everything else

Sympathetic Nervous System

part of the PNS and autonomic nervous system

fight or flight

Parasympathetic Nervous System

part of the PNS and autonomic nervous system

maintains homeostasis

rest and digest

Neurons

specialized cells that transmit nerve impulses

larger cells in nervous system

Glia

help neurons do their job more effectively and efficiently

more numerous in nervous system

multiple types (astrocytes, microglia, schwann cells, and oligodendrocytes)

may be able to signal to each other and be involved in conciousness

may play a role in schizophrenia, bipolar disorder, endocannabinoid signaling, and addiction

Astrocytes

type of glial cell

provide structural support, maintain ionic and chemical environment, store nutrients to provide energy for neurons, perform gliosis, regulate CNS blood flow, and coordinate reciprocal glia-neuron activity

Microglia

type of glial cell

perform phagocytosis and provide immune system function

Schwann Cell

type of glial cell

form myelin sheath on a single axon in the PNS, release growth factors following neuron damage, and provide a channel to guide axons to targets

Oligodendrocytes

type of glial cell

form myelin sheaths on multiple axons in the CNS and inhibit regrowth of axons following neuron damage

Soma

cell body (where nucleus and DNA are)

where most of the day to day metabolic activity of the cell occurs

receives information (neurotransmitter receptors)

Dendrites

extend from the cell body

receives information (neurotransmitter receptors)

Axon

usually one per neuron, may branch but not a lot and at a significant distance from cell body

send the electrochemical signal (action potential) at 224-240 mph

inside myelin sheath

can be short or long and keep diameter for entire distance

Myelin Sheath

cover the axon to allow it to send signals faster

there are multiple disorders of it

can be regrown

White Matter Diseases

diseases of the myelin sheath

MS is an example

Multiple Sclerosis (MS)

autoimmune disorder where the immune system attacks myelin

white matter disease

challenging to diagnose because there are a lot of things that look like it and the problems depend on where demyelination occurs

treated with drugs that suppress the immune system

Terminal Buttons/Presynaptic Nerve Terminals

where neurotransmitters are released

information sending part of a neuron

Neurogenesis

formation of neurons, particularly adult ones

in certain places, the adult brain can make more neurons

depression has been linked to lack of this and some drugs promote it

Neuroplasticity

the ability of our neurons to rewire and make new and different connections

we used to think this was fixed in place

Neuromodulators/Neuropeptides

may enhance, reduce, or prolong the action of a neurotransmitter

volume transmission

Classical Neurotransmitters

chemicals released between synapses

100+ identified in the brain

effects restricted to a single synapse

Synapse

point of communication between cells

most psychoactive drugs work by altering neurotransmission here

three different types

Non-Classical Neurotransmitters

made by enzymes in the postsynaptic cell and affect the activity of the presynaptic cell (retrograde transmitters)

gas transmitters and endocannabinoids

not stored/made on demand

release triggered by postsynaptic receptor activation

Volume Transmission

diffuse away from the site of release to influence other cells

Hormones

released from glands into the blood stream and carried to many different parts of the body

produce more global effects

Axodendritic Synapses

axon links to dendrite

most cells

Axosomatic Synapses

axon links to soma

common

Axoaxonic Synapses

axon links to other axon

Chemical Events at the Synapse

synthesis of NTs by neurons

transportation of some NTs to nerve terminals

storage of NTs in synaptic vesicles

release of NTs from nerve terminal after action potential

NTs diffuse across synapse and bind reversibly to receptors

inactivation of neurotransmitters

Ligand

molecule that binds to a receptor with some selectivity

Affinity

the ability of a ligand to bind to a receptor

can be stronger or weaker

Potency

measure of the amount of drug required to produce a specific effect

relative term

Efficacy

the absolute ability of a drug to produce an effect

Postsynaptic Receptors

receptors on postsynaptic cell that produce an effect on that cell

Presynaptic Receptors

receptors on presynaptic cell typically found on axoaxonic synapses

Autoreceptors

presynaptic receptor that is sensitive to the neurotransmitter released by that neuron to act as a negative feedback mechanism for synthesis and release

Terminal Autoreceptors

autoreceptors that regulate neurotransmitter release at axon terminal

Somatodendritic Autoreceptors

autoreceptors that regulate the neuron’s overall firing rate

found on soma and dendrites

Reuptake Transporters

take neurotransmitter molecules back up and repackage them

Heteroreceptors

presynaptic receptors found at axoaxonic synapses that are sensitive to other neurotransmitters

involved in presynaptic facilitation and inhibition

Factors That Influence What Happens When a Neurotransmitter Binds to a Receptor

what type of receptor it binds to/what it does chemically to the cell

what receptor subtype

Ionotropic Effects

affect postsynaptic membranes

ligand-gated channel receptors

quick start with short duration and localized effects

immediately open/close ion channels and change the probability of a neuron firing an action potential

used for quick events like visual stimulation and muscle contraction

Metabotropic Effects

post and presynaptic

second messenger- G-protein coupled receptor

late start with duration up to hours or more

intracellular chemical cascade

activated G-protein inside membrane which activates a second messenger system (G protein effector enzymes, increase/decrease synthesis of second messenger, subsequent intracellular changes)

can have broad effects on ion channels, protein synthesis, and gene expression

Excitatory Post Synaptic Potential (EPSP)

increases the chance of a neuron firing an action potential

Inhibitory Post Synaptic Potential (IPSP)

decreases the chance of a neuron firing an action potential

Threshold Value of Neurons

value that, when reached, sodium channels are opened and an action potential is triggered

weigh EPSPs and IPSPs

Ways to Inactivate Neurotransmitters

enzymes around synapse break down neurotransmitter

reuptake transporters take neurotransmitter up out of the synapse to be repackaged and used again

neurotransmitter may drift out of the synapse and get picked up by glial cells (particularly if there are a lot)

Agonist Drug

drug that increases or mimics the effects of a neurotransmitter

Antagonist Drug

drug that blocks or decreases the effects of a neurotransmitter

Inverse Agonist

drug which produces an effect opposite to that of the agonist by occupying the same receptor

example: some benzodiazapines (not the common ones)

Partial Agonist

drug that binds to a receptor and exerts only part of the action exerted by the endogenous neurotransmitter or produces a submaximal receptor response

example: buprenorphine (Buprenex)

Mixed Agonist-Antagonist

act as agonists at some receptors and antagonists at others

example: aripiprazole (Abilify) partial agonist at D2 and 5HT1 and antagonist at 5HT2

Causes of Side Effects

drugs acting on multiple pathways of a neurotransmitter

drugs acting on multiple neurotransmitter receptor subtypes

drugs acting on multiple neurotransmitter systems

genetic polymorphism of metabolic enzymes

genetic polymorphism of neurotransmitter receptors

drug/drug and drug/food interactions

drug additives

Effects of Chronic Drug Administration on Neurotransmission

homeostasis, allostasis, & learning changes

changes in receptor number (up or down)/cellular tolerance

changes in receptor sensitivity

changes in neurotransmitter synthesis or release

neurotoxicity

Allostasis

the body's ability to maintain stability through change by resetting the set point

Additive Effects

combined effects equal to effects of each drug alone

example: Aspirin and Advil (pain relief)

Synergistic/Hyperadditive Effects

combined effect greater than the effect of each drug alone

example: barbiturates and alcohol (respiratory depression)

Potentiation

a type of synergistic effect where the combined effect is greater than the effect of each drug alone because one drug enhances the effect of another even if it has little effect itself

example: fluoxetine and cocaine (heart rate)

Antagonism Drug Interaction

combined effect less than the sum of each drug alone

example: naloxone and heroine (respiratory depression)

Mithridatism

the practice of gradually ingesting or self-administering non-lethal dosed of poison to build immunity to it

Tolerance

repeated administration of a drug reduces the drug's effect

need higher dose to get same effect

reversible when drug use stops

varies by drug, drug effect, and degree

influenced by dose, frequency of use, and environmental factors

Cross Tolerance

tolerance to one drug will effect tolerance to a similar drug

Tachyphylaxis

the rapid development of tolerance

example: nausea effects of opioids and nicotine

Metabolic/Dispositional/Pharmacokinetic Tolerance

tolerance due to enzyme induction

Neuronal/Cellular/Pharmacodynamic Tolerance

tolerance due compensatory changes at synapses

Behavioral/Conditioned/Context Specific Tolerance

the environment influences the development of tolerance

Operant Conditioning Tolerance

type of behavioral tolerance where practicing under the influence allows for the avoidance of punishment (not doing something well)

Classical Conditioning Tolerance

type of behavioral tolerance where there is a loss of ability to affect the body's response to a drug

conditioning of homeostatic compensatory responses

Operant Conditioning

behavior changes based on reward and punishment

Classical Conditioning

pair something that will automatically elicit a response with a neutral stimulus, the stimulus will eventually elicit the same response

Drug Sensitization

reverse tolerance

repeated administration of a drug will produce an increased response

Placebo Effect

a pharmacologically inert substance elicits a therapeutic response

can mimic pharmacoligical effects and side effects

Single Blind Study

the person taking the drug does not know if they are getting a drug or placebo, but the person administering knows

researcher bias is a limitation

Double Blind Study

neither the participant nor the person administering the drug and collecting data knows if it is the drug or placebo

Active Placebo

a placebo that may have some small effects

used to make it more difficult for people to guess if they have had the drug or placebo

Ethical Considerations of Placebos

the placebo group could end up dead

use in clinical practice is not illegal

the AMA says it is not ethical unless consent is given

Nocebo Effect

people get worse because of negative expectancy