Meds & Behavior Test 1

Action Potential

Complete depolarization of the neuronal membrane from -70 mV to approximately +40 mV

Autoreceptors

receptors located on the terminal button or cell body that receive neurotransmitters released from their terminal button; control neurotransmitter synthesis and release

Central Nervous System (CNS)

consists of the brain and spinal cord

Excitatory Postsynaptic Potentials

graded membrane potentials that depolarize the neuron bringing it closer to its firing threshold

Excitotoxicity

a consequence of a high rate of presynaptic activity on a neuron resulting in excessive CA++ influx and eventual cell death

Graded Potential

small changes in a membrane’s resting potential; may be excitatory and depolarize the membrane from -70 mV to -60 mV, or they may be inhibitory and hyperpolarize the membrane to -75 or - 80 mV

Heteroreceptors

receptors located on the terminal button or cell body that receive neurotransmitters released from another neuron; control neurotransmitter synthesis and release

Inhibitory Postsynaptic Potentials

graded membrane potentials that hyperpolarize the neuron, making it less likely to fire

Interneurons

reside only within the central nervous system and function to bridge communication between sensory and motor neurons

Ion Channel

a protein embedded in the cell membrane that controls the movement of charged ions across the cell’s membrane

Ionotropic Receptors

a receptor that directly controls an ion channel on the cell membrane

Neocortex

(latin for new cortex, since it was the last part of the brain to develop during evolution) The outer layers of the cerebral cortex

Neural Integration

the process of summation of all excitatory and inhibitory potentials on the cell of receiving neurons

Neuromodulator

A substance produced and released by neurons or glia that alters cell functioning; may alter the effects of neurotransmitters at synapses and, unlike neurotransmitters, they may act at greater distances from the releasing cell.

Neurotransmitter Reuptake

the process of removing neurotransmitter substances from the synaptic gap back into the terminal button by a transporter protein

Nigrostriatal Pathway

dopamine neurons originating in the substantia nigra of the brain stem and project to the striatum of basal ganglia

Node of Ranvier

a small gap in the myelin sheath that surrounds the axon of the neuron. The membrane of the axon is exposed to the extracellular environment at these gaps

Orexin

a peptide neurotransmitter produced by cells within the lateral hypothalamus; a powerful appetite stimulant and plays a significant role in sleep-wake cycles

Peripheral Nervous System (PNS)

transmits and receives information to and from our muscles, glands, and internal organs, and to our skin

Phosphorylation

the adding of a phosphate molecule to the ion channel protein; results in a change in the protein configuration allowing for charged ions to pass through it

Pituitary gland

attached to the base of the hypothalamus by the pituitary stalk; responsible for the production and secretion of a variety of essential hormones.

Resting Potential

the state of a neuron when the ionic electrostatic and diffusion forces are at equilibrium; may vary between -60 and -70 millivolts depending on the neuron and its location

Reticular Activating System

noradrenergic and cholinergic neurons originating in the brainstem and projecting via the thalamus to the cortex

Second Messenger

a substance within the cell that becomes activated during cell signaling; initiate biochemical processes that result in opening or closing ion channels, the activation of cell enzymes or hormones, and the expression of genes

Tardive dyskinesia

a severe motor disorder characterized by facial tics, lip smacking, tongue extension, and rapid eye blinking. Can be caused by long-term use of antipsychotic medications

Roughly, how many neurons do we have in our bodies?

200 billion (but some say 100)

What are the catecholamines?

D dopamine
E epinephrine
N norepinephrine

What is the chemical name of Serotonin?

5 - Hydroxytryptamine (5-HT)

What are the 4 dopamine pathways?

1. Nigro-Striatal Dopamine Pathway
2. Mesolimbic Dopamine Pathway
3. Mesocortical Dopamine Pathway
4. Tuberoinfundibular Dopamine Pathway

What are the sensory (afferent) neurons?

ascending messages TO CNS from PNS

What are the motor (efferent) neurons?

descending messages FROM CNS back to PNS

What are Interneurons?

bridge communication between sensory and motor neurons

What is diffusion?

pressure to move from higher to lower concentration

What is electrostatic potential?

similarly charged ions repel each other

What is the communication within the cells/neurons?

Electrical processes

What is the communication between the cells/neurons?

Chemical processes

What is the all-or-none law?

neuron fires at one level of intensity

What two things make the speed of an action potential faster?

longer and myelinated neurons

Neurons that _____ together, _____ together

neurons that fire together, wire together

What's the result of unmyelinated neurons?

slows impulses as seen in MS

What are the two receptor types?

Ionotropic and Metabotropic

Describe the ionotropic receptors.

More direct, quickly depolarize, controls ion channel directly

Describe the metabotropic receptors.

More indirect, exerts its effects indirectly

What neurotransmitter is the primary excitatory?

Glutamate

What neurotransmitter is the primary inhibitor?

GABA

What is the Neuraxis?

an imaginary line drawn through the spinal cord up to the front of the brain

What is the anterior (rostral) side?

toward the head (beak)

What is the posterior (caudal) side?

toward the tail

What is the ventral (inferior) side?

toward the “belly”

What is the dorsal (superior) side?

toward the back (top of the head)

What is the ipsilateral location?

same side of brain

What is the contralateral location?

opposite side of the brain

What are the three planes of the brain?

Sagittal, coronal (transverse), and horizontal

What is the “bark” of the brain?

the cerebral cortex

What is the cerebral cortex?

forms the outer layer of the cerebral hemispheres (approximately 3mm thick)

What are the two types of grooves on the cortex surface?

sulci (small grooves) and fissures (large grooves)

What are the bulges in the cortex called?

gyri

What was the 1st discovered Chemical agent?

Acetylcholine

What are muscarinic receptors?

metabotropic

What are nicotinic receptors?

ionotropic

Agonist

a substance that facilitates or increases neural transmission

Antagonist

a substance that inhibits or decreases neural transmission

Associative tolerance

a decrease in responsiveness to drugs that is controlled by cues associated with drug use and onset

What is a consequence of classical/Pavlonian conditioning?

Conditioned tolerance

Behavioral tolerance

learned behavioral adaptations that occur in a drug state and contribute to enhanced motor performance; also referred to as state dependent learning

Blood-Brain Barrier (BBB)

a relatively impermeable membrane forming and surrounding capillaries in the brain that prevents most substances from leaving the circulatory system and entering the brain

Brand name

a drug’s brand or trade name is a name given by its manufacturer and is used in advertising the drug; it is protected by a patent

Cellular tolerance

cellular adaptations to some drugs that diminish their effects on target cells

Chemical name

reveals its chemical composition and molecular structure

Cross-tolerance

tolerance to a drug in the same class as the drug administered repeatedly; may be observed to codeine after it has already developed to morphine

Depot binding

drug binding to inactive sites

Dose response curve

the relationship between a drug dose and its physiological effects; relationship is often sigmoidal

Double-Blind

neither the patients nor the physician know which patient group receives the placebo or the actual medication; can eliminate both subject and researcher bias, which may affect the outcome of drug trials

Downregulation

a decrease in neurotransmitter synthesis or release caused by drug action on target receptors; may also involve decreases in receptor availability

Generic drug

*must contain the same active ingredients as the original brand name drug and they must be pharmacologically equivalent. b/c several manufacturers may compete to produce and market generic drugs, their cost is often considerably less than their equivalent brand-named drug

Half-life

the amount of time it takes for a drug’s blood level to be decreased by metabolism and elimination by 50% (half of its peak blood level)

Metabolic tolerance

metabolic enzymes that break drugs into water soluble compounds actually increase in availability after repeated exposure to that drug; results in more rapid metabolism as more enzymes are available for degradation

Cytochrome P450

a class of liver enzymes responsible for the metabolism of many psychoactive drugs

Pharmacodynamics

the science of the mechanisms of drug action or how drugs affect target cells and induce pharmacological effects

Pharmacokinetics

the science of how drugs are absorbed, distributed to body tissues, and eliminated from the body after metabolism

Placebo

a pharmacologically inert substance administered under the guise of medication

Respiratory depression

a decrease in respiratory depth and frequency caused by inhibition of respiratory centers in the brain stem; often the cause of death from drug or alcohol overdose

Reuptake

a process where neurotransmitter substances are removed from the synaptic gap and returned to the terminal button of the transmitting neuron; decreases the availability of the neurotransmitter at the receptor sites

Selective Serotonin Reuptake Inhibitors (SSRIs)

a class of antidepressant drugs that selectively inhibit serotonin reuptake, leaving serotonin available at receptor sites

Therapeutic Index

the range between a drug’s therapeutically effective dose and its lethal or toxic dose; can decrease as tolerance develops

Tissue Equilibrium

when the concentrations of a drug in the blood and surrounding tissues are essentially the same

Tolerance

a decrease in the effectiveness of a drug after repeated administration; this is observed as a shift to the right in the dose response curve

What does the Henderson-Hasselbalch equation measure?

fat-solubility

What does “philic” mean?

“love”

What does “phobic” mean?

“oppose”

What does it mean if a drug has a lot of fat molecules?

it will be more rapidly absorbed

Low serotonin = what?

low impulse control

What is the threshold dose?

minimally effective dose (just large enough to produce detectable change)

What is the maximum dose?

greatest degree of response achievable with drug

What is the effective dose (ED)?

median effective dose - works for 50% of people

What is the lethal dose (LD)?

minimal dose that is capable of producing death in a certain percentage

What is the therapeutic index (TI)?

margin of safety; relationship between lethality and effectiveness

Can you overdose on Benzodiazepines?

no

Active Placebo

a psychologically inactive drug that has some peripheral side effects that patients may recognize and thereby assume they are receiving actual treatment. (example: dry mouth, dizziness, or blurred vision)

Agoraphobia

“fear of the marketplace” the fear of being in open places where a panic attack may occur and from which it would be difficult to escape or help would be unavailable