BIOPSYCH: 2.2

AMPT

(Alpha-methyl-para-tyrosine) temporarily blocks the production of dopamine. (no current theraputic use but helpful to researching dopamine)

Modified amino acid

(One-member family) chemical similar to an amino acid, except includes an N(CH3)3 group (not (NH2)); only Acetycholine.

how are Neuropeptides (Neuromodulators) different from other transmitters?

-neuropeptide effects last for longer periods of time (wide diffusion) duration: lasts for minutes instead of a few seconds -transmitters-axon/ peptides- dendrite -peptides are synthesized in the cell body, instead of axon terminals -Neuropeptides require repeated stimulation (depolarazation)

Reuptake

-process of detaching and taking the usable released neurotransmitter molecules still in tact and reusing them; -occurs in transporters (membrane proteins) -process is used with seratonin and catecholamines (dopamine, norepinephrine, and epinehrine) ****Acetycholine does not undergo this process, it breaks down into acetate and choline and is recycled.

The sequence of chemical events at a synapse (7 parts)

1. Neuron synthesizes chemicals that serve as neurotransmitters. (smaller neurons are synthesized in axon terminals/ neuropeptides synthesized in the cell body) 2. Action potentials travel down the axon. CALCIUM enters and releases neurotransmitters into the synaptic cleft. 3. released molecules diffuse across the cleft, binds to receptors, and alter the activity of the postsynaptic neuron. 4.neurotransmitter molecules separate from receptors. 5. Reuptake of neurotransmitter by transporter protein 6.Some postsynaptic cells release retrograde transmitters that slow further release from presynaptic cell. 7.Negative feedback sites respond to retrograde transmitter or to presynaptic cells own transmitter.

Purines

A category of chemicals including adenosine and its derivatives; Adeonsine Triphosphate & adenosine, maybe some others

Amino Acids

Acids containing amine group (NH2) Include:Glutamate, GABA, glycune, aspartate

Types of neurotransmitters

Amino acids (and a modified amino acid), monoamines, neuropeptides (chains of amino acids), purines, and gases.

Stimulant drugs

Amphetamine (adderall), cocaine, and methylphenidate (ritalin) increase the amounts of dopamine and are broken down by COMPT faster than the presynaptic cell can replace. after taking a stimulant the user undergoes a withdrawal state: reduced energy, motivation, and mild depression)

COMPT (Catechol-o-methyltransferase)

An enzyme that takes the products not taken up by the transporter and breaks them down and will eventually show up in urine and blood

Posterior pituitary

Brain; produces oxytocin, ad vasopressin

When the action potential reaches the presynaptic terminal, which ion must enter the presynaptic terminal to evoke release of the neurotransmitter?

Calcium

Carbohydrates

Can increase tryptophan entry. Carbs increase levels of insulin, takes some of tryptophans competitors out of blood cells and into body cells (decreases competition)

Exocytosis

Caused after calcium releases into the presynaptic terminal. Exocytosis are bursts of release of neurotransmitters from the presynaptic terminal. (Neurons can release a single or combo of transmitters simultaneously or at different times)

Neuropeptides

Chains of amino acids, Includes: endorphins, substance P, Neuropeptide Y, many others.

Horomone

Chemical secreted by cells in one part of the body and conveyed by blood to influence other cells. produce long lasting changes in different parts of the body.

Monoamines

Chemicals formed by a change in certain amino acids. include: indoleamines; Seratonin catecholamines: dopamine, norepinephrine, epinephrine

Ondanesterone

Creates a variation in receptors. Seratonin receptor type3 mediates nausea, but the drug blocks that particular receptor and relieves nausea (common use in cancer patients)

Many neurons release neuropeptides mostly from the:

Dendrites

Opiate drugs

Derived from opium poppy. (morphine, heroine, ans methadone) bind to endorphine receptors to temporarily relieve pain

Phenylketonuria

Diagnosed lack the enzyme that converts Phenylalanine to tyrosine. They can get tyrosine from diet but must restrict amounts of Phenylalanine.

Hallucinogenic drugs

Distort perception, such as LSD- chemically resemble seratonin. attach to seratonin type 2A receptors and provide stimulation at inappropriate times and last longer than usual.

Metabotrophic synapse

Effects are slower and longer; also able to send different messages. (uses seratonin, norepinephrine, dopamine amd sometimes gluatmate and GABA) Influences activity all over the brain. needed for longer intake of info i.e. smell, taste, and pain.

MAO (Monoamine oxidase)

Enzyme which breaks down transmitters (Norepinephrine, seratonin, and dopamine) into inactive chemicals.

Adrenal medulla

Epinephrine and norepinephrine; similar to actions of sympathetic nervous system

Name the three catecholamine neurotransmitters

Epinephrine, norepinephrine, and dopamine :)

Ovary

Estrogen and progesterone; female sex characteristics and pregnancy

Acetycholine

Excitatory transmitter as most ionotrophic are.

The neuron excretes neurotransmitter through its membrane by a process called:

Exocytosis

Suppose you were bitten by a black widow spider whose venom increases the release of acetylcholine from the presynaptic terminal. Which of the following treatments would be most effective?

Increase the activity of acetylcholinesterase.

Growth hormone

Increases body growth

Prolactin

Increases milk production

ACTH

Increases steroid hormone; adrenal gland

Glycine

Inhibitory transmitter; found in the spinal cord

Ion channels

Leaking channels; alternate between open and close

Fat cells

Leptin; decreases appetite

What were the first type of antidepressant drugs discovered?

MAO inhibitors; blocked MAO and increased the brains supply of Seratonin, Dopamine, and Norepinephrine. Exactly how they relieve depression is still not certain.

Pineal gland

Melatonin hormone- sleepiness and plays a role in puberty.

Glutamate

Most excitatory ionotrophic synapses use this neurotransmiiter; most abundant in the nervous system.

Gases

NO (Nitric Oxide) and possibly others

GABA (Gamma-aminobutryric acid)

Neurotransmitter used by inhibitory ionotrophic synapses; opens chloride gates, enabling chloride ions (neg charge) to cross the membrane more quickly

Chemical Gated Channels

Open and close in response to a specific chemical stimulus. (ions, neurotransmitters, and horomones)

Voltage gated channels

Open in response to a changw in membrane potential (voltage) ex. sodium and potassium channels

G-protein couple receptor

Opens channels by taking the ions; coupled to guanosine triphosphate (GTP) energy storing molecule. results in increased concerntration of the 2nd messenger.

Phanylalanine and tyrosine

Phenylalanine and tyrosine are amino acids present in proteins they are precursors of dopamine, norepinephrine, and epinephrine.

More neg feedback

Postsynaptic neurons can respond to stimulation by releasing chemicals such as nitric oxide, anandamide, ams 2-AG

L-dopa

Precursor to dopamine. alters synthesis of transmitters. helps increase supply of dopamine. (useful for patients w/ Parkinson's Disease)

methylphenidate

Prescribed for ADHD both ritalin and cocaine block the reuptake of dopamine also. differ in dose and time course coke- rapid excitement ritalin gradual increase in excitement differ due to ways of ingestion. coke is snorted or injected, while ritalin is taken as a pill, however, if ritalin is snorted or injected the effects are similar

Nicotine

Present compound in tobacco stimulates a family of acetylcholine receptors (nicotine receptors). Increases dopamine release blocking the dopamine causes a decrease in pleasure and motivation

Endocrine glands

Produce horomones

oxytocin

Promotes uterine contractions, milk release, and sexual pleasure.

Aldosterone

Reduce release of salt in urine

Kidneys

Renin-regulates blood pressure, contributes to hypovolemic thirst.

Autoreceptors

Resond to the released transmitter by inhibiting further synthesis and release. provide negative feedback.

Testis

Testosterone- male sex characteristics and pubic hair

Endorphins

a contraction of endogenous morphines. Kick in after exercising.

Acetylcholine

acetyl+choline=acetylcholine Acetyl-synthesized from metabolism Choline- from diet. acetylcholine is found in milk, eggs, and peanuts.

Cannabinoids

active chem in marijuana bimd to anandamide or 2-AG receptors. attachment of cannabinoids indicate the cell got your message, stop sending it while the presynaotic cell, unaware that no messages were sent at all, stops sending it. results in: decrease of both excitatory and inhibitory messages from many neurons.

Adrenal cortex

aldosterone, cortisol.

The chemicals used as neurotransmitters in humans are found in:

all other species

"Second messengers" carry their messages to:

areas within the postsynaptic cell.

When an action potential reaches the end of an axon, the depolarization causes what ionic movement in the presynaptic cell?

calcium into the cell

Transmitter (or ligand) gated

channel that is controlled by a neurotransmitter; when the neurotransmitter attaches, the gates open.

Loewi demonstrated that synapses operate by the release of chemicals. He did this by:

collecting fluid from a stimulated frog's heart, transferring it to another frog's heart, and measuring that heart rate.

Glucagon

converts stored fats into blood glucose.

Activation of autoreceptors tends to:

decrease further neurotransmitter release.

Ionotrophic synapse

effects are faster and shorter effect (depend on GABA or Glutamate) localized to one point of the membrane. needed for fast intake of info i.e. vision or hearing

Cortisol

elevates blood sugar and metaolism

Neurotransmitter is to ____ as cyclic AMP is to ____.

first messenger, second messenger

Tryptophan

found in diet Precursor of seratonin; amount in diet controls amount of seratonin in the brain. transports through BBB by special system shared with larger amino acids. Can increase tryptophan by decreasing phenylaline in the diet, or by eating carbs.

The anterior pituitary is composed of ____ and the posterior pituitary is composed of ____.

glandular tissue; neural tissue

insulin

helps glucose enter cells

Vesicles are located:

in presynaptic terminals.

Where are most neurotransmitters synthesized?

in the Presynaptic terminal; stored both outside and inside of the vesicles (excluding Nitric Oxide)

hypothalamus

in the brain; releases various hormones. promote/inhibit release of horomones from pituitary gland

Anterior pituitary gland

in the brain; thyroid stimulating hormone, luteinizing hormone, follicle-stimulating hormone, ACTH, and prolactin

Glutamate opens sodium gates, enabling sodium ions to enter the postsynaptic cell. What is this effect called?

increases blood flow to certain areas of the brain.

A receptor can directly open a channel exerting a(n) ____ effect or it can produce slower but longer ____ effects.

ionotrophic; metabotrophic

Reuptake is the absorption of:

neurotransmitters by the presynaptic neuron.

Nitric Oxide

oddest transmitter, gas released by small local neurons. Poisonous in large amounts. Related to blood flow/dilation of the blood vessels. When a part of the brain becomes highly active, blood flow INCREASES.

Follicle-stimulating hormone

promotes ovum maturation (females) sperm production (males)

Vasopressin

raises blood pressure; decrease urine volume.

Ionotropic effects are characterized by:

rapid, short-lived effects.

(study Figure 2.14 pg 50) Catecholamines

relationship of epinephrine, norepinephrine, and dopamine compounds. These both contain a catechol group and an amine group.

Otto Loewi

repeatedly stimulated the vagus nerve (decreased the heart rate) in a frog. Transferred the fluid of the heart onto a second frog and found that it also decreased. However, stimulating the accelorator nerve increased the heart rate. Discovered that stimulating a different nerve released released something to change the heart rate. conclusion: nerves send messages by releasing chemicals.

After a meal that was rich in the amino acid tryptophan, which neurotransmitter level would be increased the most?

serotonin

In general, a single neuron releases ____ neurotransmitter(s) and can respond to ____ neurotransmitter(s).

several; many

Synaptic cleft

space between presynaptic and postsynaptic neurons.

Luteinizing hormone

stimulates ovulation

thyroid stimulating hormone

stimulates thyroid gland

Pancreas

stomach; insulin and glucagon

What provides the building blocks for synthesizing all neurotransmitters?

substances found in the diet

The presynaptic terminal stores high concentrations of neurotransmitter molecules in:

vesicles