PSY 459 Exam 1 - University of Kentucky

University of Kentucky PSY 459 Exam 1 FA 2025 with Dr. Mark Prendergast

Pharmacokinetics

what the body does to a drug

Bioavailability

amount of drug in blood that is free to bind at targets

Intravenous

injection. rapid + accurate, reaches brain in 45 seconds

Inhalation

absorbed fast through lungs.

Intramuscular

into blood via muscles: epi pens

Intranasal

local effects of relieving Conjestion. Full absorption ~ 15 min

Subcutaneous

under skin very slow.

Rectal

reaches brain in minutes. Bypasses FPM. Dangerous if misused

Oral

most common, safe. low bioavailability due to Stomach acid + FPM.

First Pass Metabolism

Chemical alteration of a drug by liver prior to entering the blood + heart - Avoids FPM: IV, inhalation, rectal

Three Ways Drugs Enter Cells

1) Opening neurotransmitter receptor

2) Active transport

3) Passive diffusion

Lipophilicity

the ability of a substance to mix with oily + Fatty substances

How do lipophilic drugs enter cell membrane

Through passive diffusion

Most recreational drugs are this but alcohol is not

Lipophilic

Blood Brain Barrier

No blood touches brain except at area postrema. Fetuses have no blood brain barrier

Area Postrema

vomit center, senses toxins

Drug Depots

binding that occurs at inactive Sites - Blood proteins, muscle, hair + lipids.

-Prevents drug from releasing quickly.

First-Order Kinetics

drug clearance from blood in the liver, constant

Half-Life (T 1/2)

time it takes for concentration to drop 50%

How many half-lives does it take to metabolize a drug

5 to 6

Zero-Order Kinetics

deug is cleared at a constant rate of 0 regardless of concentration

Enzyme Induction

the repeated use of enzymes and speed of metabolism, builds drug/cross tolerance and metabolic tolerance

Pharmacodynamics

how the drug alters the body, receptors and ligands

Efficacy

max effect a drug can produce no matter the dosage

Potency

amount of the drug needed to produce the desired effect

Partial Agonist

binds to agonist site but produces partial effect - helps prevent cravings

Competitive Antagonist

binds to agonist site to block agonist - can be overcome by increasing the agonist concentration

Non-Competitve Antagonist

binds to a different neuron site than agonist, like having two light switches.

PAvlovian Conditioning

reflexive effects - the drug taking procedure or the environment may elicit a conditioned responce before even taking the drug

Threshold

-55 mV, starts action potential process

Depolarization

Na+ channels open, Na+ is moved into the cell, polarity rises to +40 mV

Action Potential

K+ channels open and K+ is moved out of the cell

Repolarization

Polarization moves toward RMP, Na+ channels close

Refractory Period (Hyper Polarization)

K+ channels close, drops below RMP briefly before returning to -70 mV

Hyperpolarization

decrease in membrane potential causing neuronal inhibition

When action potential reached the end of an axon

a) reaches Ca²⁺ channel

b)Ca²⁺ flows in

c) vesicles burst, sharing signal - reabsorbed by synaptic vesicles

Forebrain

Cerebral cortex, thalamus (sensory relay), and hypothalamus (regulatory behavior)

MIdbrain

Motor function, vision, and auditory function

Hindbrain

Medulla (essential bodily functions), pons (sleep, wake functions), cerebellum (movement, motor memory)

Somatosensory Cortex

region of the parietal lobe that posses sensory information, controls hallucinations

DIencephalon

Thalamus, hypothalamus, mammillary bodies, and optic chiasm

Thalamus

sensory relay nuclei

Hypothalamus

above pituitary gland, endocrine function, motivated behaviors/regulatory behaviors (eating, sleeping, sex, temperature, thirst)

Mammillary bodies

learning, memory

Optic Chiasm

some optic nerves cross over

What is around the thalamus and hypothalamus?

the basal ganglia

Limbic System

regulates emotion

Basal Ganglia

regulates movement, habit formation, is dysfunctional in Parkinson’s disease

Afferent sensory infor (doral) horn

Can be inhibited

Guanine binding receptors

3 classes, all are tumeric proteins, similar but differ in 1 subunit

Gs

stimulatory, can activate adenylate cyclase, stimulates cAMP, open Ca²⁺

Gi

inhibitory, inhibits adenylate cyclase, activates K+ channels, some inhibit Ca²⁺ channels

Synapses

point of communication between neurons, usually in one direction pre synaptic to postsynaptic

Heteroreceptors

receptors for other transmitters released at axonal synapses

Transporter 

proteins in the cell membrane take up transmitter molecules into a cell

Reuptake

transmitters taken up by the cell that released them

What type of drug metabolism allows for blood alcohol levels to increase when we drink more than 1 drink an hour?

zero-order kinetics

What forms the blood brain barrier?

astrocyte feet

What type of antagonist reduces the POTENCY of an agonist?

competitive

What type of drug would reduce the EFFICACY of an agonist?

non-competitive antagonist

Allowing Cl- to flow into a neuron will have what effect on the resting membrane potential?

hyperpolarization

Which subsection of the brain includes the medulla?

hindbrain

Activity of which brain region will be disrupted by use of hallucinogens?

somatosensory cortex