NEUR200- Exam 1 Material Part 2

What is bioavailability?

the amount of “free” or unbound drug in the bloodstream

How do pharmeceutical companies manipulate bioavailability?

by using polymers to cause a slow release of drug and altering hydro- and lipo-philic properties

how do polymers cause a steady state of drug releaes?

polymers degrade layer by layer: water from blood comes in contact with polymer, water enters first polymer layer causing a hydrogel to form, drug in that layer dissolves in the water, and the dissolved drug diffuses out from high to low concentration into the blood stream

What is Depot binding?

when a drug binds to inactive receptors, causing less drug bind to actual active receptors

Depot binding helps explain why…

small doses are often not effective at first (depot sites hoard the drug first) and why drug action is prolonged even after a drug is stopped (inactive receptors will slowly release the drug after active drug levels drop)

What kind of sites are depot binding?

plasma proteins, muscle, or fat

Example of a protein depot binding site is..

serum albumin (a plasma protein) found in blood that binds lipophilic drugs

What is competitive binding?

when a drug/substance binds to the same site as the NT

What is noncompetitive binding?

when a drug/substance binds to a different allosteric site on the receptor

What is affinity?

the strength of chemical attraction to the target receptor

A higher affinity drug is is more..

potent and produces a greater/prolonged response

What is first order kinetics?

the rate that most active substances are eliminated from the blood stream; depends on ½ life

what is the 6 half-life rule?

states that if a drug is regularly dosed on its ½ half , then it will take 6 half lives to reach a peak concentration in a steady-state

After 6 half lives, how much drug is eliminated?

98.4% of drug is eliminated

How does first order kinetics and the 6 half life rule impact dosing and steady state concentration?

Dosing will be based on a drugs half-life because drug concentration in the bloodstream will accumulate safely, allowing it to reach its peak concentration. It will reach steady-state because a fraction of the previous drug dose is still in the system when the next dose is taken and so eventually the amount of drug coming in will be equal to the amount being eliminated after 6 half lives.

What is zero-order kinetics?

when increasing the concentration of drug won’t change the reaction because a constant amount of drug is processed per hour

zero-order kinetics typically happens when..

enzymes that break a certain drug down are fully saturated leading to a constant rate of elimination regardless of concentration. ( kind of like the rate-limiting step!)

What is Phase 1 Metabolism?

non-synthetic reactions where a drug is chemically modified and breaks into active metabolites through events like oxidation reduction and hydrolysis

Examples of phase 1 metabolism are..

alcohol dehydrogenase and cytochrome P450

What is Phase 2 Metabolism?

synthetic reactions where a drug transforms into inactive states by being ionized or less lipid soluble and is broken down

What is enzyme induction?

when a drug enhances the expression of an enzyme

What is enzyme inhibition?

when a drug inhibits or interferes with expression of an enzyme (can be competitive or noncompetitive)

What is tolerance?

when repeated exposure to a drug produces a decrease in sensitivity to the drug (larger dose required to obtain the effect)

A high tolerance produces what kind of shift on a dose response curve?

a right shift

What are the 3 types of tolerance?

metabolic, pharmacodynamic, and behavioral

What is sensitization?

when repeated exposure to a drug acquires greater incentive value (a lower drug dose produces the effect)

What kind of shift is seen on a dose response curve with sensitization?

a left shift

How are drugs excreted?

water soluble drugs can be excreted whole/don’t need to be broken down while lipid soluble drugs need to be metabolized before being absorbed into the urine

Drugs are excreted through..

kidneys, lungs, sweat, saliva, milk

How does the endocrine system interact with the brain?

the endocrine system releases hormones which bind to receptors in the brain just like neurotransmitters do (neurotransmitters can be hormones)

All ova that women produce contains..

an X chromosome

Sperm that men produce is..

½ X chromosome and ½ Y chromosome

the sex of offspring depends on…

whether the sperm cell that fertilizes the ovum is X or Y

What are the two times that homrones impact sex differentiation?

during prenatal sex differentiation and puberty

What happens during prenatal sex differentiation?

sex is based on the SRY gene on the Y chromosome (sex-determining region Y)

What happens if the SRY gene is present on the Y chromosome?

other genes are turned on causing the testes and male hormones to develop

What happens if the SRY gene is absent on the Y chromosome?

the body defaults to developing female organs

What is the Wolffian System?

system responsible for male sex organs when two hormones are created (anti-mullerian and androgens)

What is the anti-mullerian hormone

part of the wolffian system which inhibits growth of the mullerian female system

What are androgen hormones?

part of the wolffian system which creates testosterone and dihydrotestosterone

What structures does the Wolffian system develop into?

epididymis, vas deferens, and seminal vesicles

What is the Mullerian system?

system responsible for the development of female sex organs

What hormones are secreted in the mullerian system?

none.

What structures does the Mullerian system develop into?

fimbriae, fallopian tubes, uterus, and inner 2/4 of the vagina

What are the primary and secondary sex characteristics?

primary: gonads (ovaries or testes), internal sex organs, and external genitalia present at birth

secondary: enlarged breasts, and widened hips or beard and deep voice appearing during puberty

What is kisspeptin?

peptide that controls the start of puberty in the arcuate nucleus of the hypothalamus

How does the hypothalamus initiate puberty?

by releasing Gonadotropin Releasing Hormone

Release of the gonadotropin releasing hormone (GnRH) leads to..

release of gonadotropin hormone from the anterior pituitary gland

How does the anterior pituitary gland cause sexual maturation?

stimulates the gonads (ovaries or testes) to secrete FSH and LH

What hormones are released in the brain that impact sexual characteristics?

two Gonadotropic Hormones: Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH)

Follicle Stimulating Hormone (FSH)

leads to ovarian follicle growth and maturation of ovum in females

Luteinizing Hormone (LH)

causes ovulation to occur and causes ovaries to produce estradiol

How does FSH and LH also work in males?

stimulates the testes to produce sperm and secrete testosterone

What is social monogamy?

a male and females social living arrangement; i.e shared territory, behavior indicative of a social pair, proximity between male and female (WITHOUT inferring any social or reproductive patterns)

How do romantic and maternal love differ?

although romantic and maternal love overlap in reward systems, they activate different brain regions

romantic love: hypothalamus, hippocampus, and ventral tegmental area

maternal love: periaqueductal grey and lateral orbito-frontal cortex