Psychobiology Ch. 4: Neurotransmitters

what are "atypical" neurotransmitters also called?

"neural messengers"

What are the steps in synaptic transmission? (7)

1. Synthesis 2. Storage 3. Transport 4. Release 5. Bind with receptor 6. Bind with autoreceptor 7. Removal and reuptake

Neurotransmitter

A molecule that changes the recipient cell's voltage by enabling ions to pass through its membrane

small amounts of _____ are released by neurons in the PNS

Carbon monoxide

The excitatory neurtransmitters are ____________ and __________ because the related chemicals (MSG and aspartame) "excite" your taste buds

Glutamate; Aspartate

The action of most neurotransmitters in the CNS is __________ whereas the action of most neurotransmitters in the PNS is _________

Inhibitory;excitatory

Which drug is able to pass through the blood-brain barrier and into the brain where it stimulates serotonin receptors and causes hallucinations?

LSD

What is known as laughing gas?

N2O

Which two things are not stored in vesicles?

NO and CO

Who discovered ACh in the frog heart?

Otto Loewi

One theory of _________ suggests that this disorder is caused by the presence of too much dopamine in the CNS

Schizophrenia

5-hydroxytryptamine (5-HT) is also known as ________

Serotonin

The two effects of neurotransmitters are...

To excite (depolarize) the receiving cells or they inhibit (hyper polarize) them

Alzheimer's

a disease characterized by progressive deterioration of a person's cognitive abilities, such as recent memories

Curare

a drug that blocks ACh, used on the tips of darts by some South American natives that hunt animals with blow guns

Atropine

a drug that blocks the action of ACh at the receptor; used as treatment for organophosphate intesticides

reserpine

a drug that disrupts the storage of monoamine neurotransmitters in vesicles, eventually causing depletion, that is, the neurons run out of neurotransmitter antagonist effect

L-dopa

a drug that increases synthesis of a neurotransmitter; a precursor of dopamine Giving L-dopa to Parkinson's patients alleviates the symptoms by allowing the remaining substantia nigra neurons to make more dopamine agonist effect

colchicine

a drug used to treat arthritis; applying colchicine to cells in a tissue culture disrupts the microtubules thus preventing transport of neurotransmitter vesicles from the soma to the terminal antagonist effect

Nitric oxide

a neural messenger that has the effect of relaxing the muscle walls of blood vessels thereby allowing blood flow to increase

Substance P

a neurotransmitter involved in sending pain messages

Oxytocin

a peptide that is released into the bloodstream as hormones which affect the uterus and plays a role in child birth

Vasopressin

a peptide that is released into the bloodstream as hormones which affects the kidneys and causes the body to retain water

Botulism

a type of food poisoning caused by improper canning. It works by blocking the release of acetylcholine antagonist

Aspartame

amino acid related to Aspartate; a common sweetener found in many food and drinks

Monosodium glutamate (MSG)

amino acid related to Glu; common taste enhancer used in Chinese and American food

"Typical" neurotransmitters

amino acid transmitters, monoamine transmitters, peptide transmitters

Aspartate (Asp)

amino acid; an excitatory transmitter in the CNS, for which there are several receptor types

Glycine (Gly)

amino acid; the main inhibitory neurotransmitter found in the brainstem and spinal cord. It is chemically the simplest amino acid and, like other amino acids, is available as a food supplement

Glutamate (Glu)

amino acid; the most common excitatory neurotransmitter in the CNS which has 8 different receptors; also a component of proteins that we eat

Gamma-aminobutyric acid (GABA)

amino acid; the most common inhibitory neurotransmitter in the CNS

In the fourth step of synaptic transmission (release), EXOCYTOSIS happens, which is when...

an action potential causes the vesicle to fuse with the presynaptic membrane and to release the transmitter into the synapse

Basal ganglia

an area of the forebrain near the thalamus.

peptide neurotransmitters

chains of amino acids; synthesized (produced) in the cell body and transported to the nerve terminal whereas the classical neurotransmitters are synthesized at the nerve terminal Peptides are the largest group of neurotransmitters

Since zinc acts on receptors and may modulate the effect of glutamate, it is a ______________

co-neurotransmitter

precursors

compounds the body uses to make serotonin

NO is found in the CNS, especially in the ______

cortex

Gases enter the postsynaptic neuron by _________ through the cell membrane

diffusing

agonistic

drugs that cause or facilitate neurotransmitter action

antagonistic

drugs that oppose or block the effects of a particular neurotransmitter

Morphine "mimics" the effect of __________

endorphins acts on same receptor sites by directly stimulating the receptor

Both ________ and ________ block the release of substance P, which is one of the ways they reduce the perception of pain

endorphins; morphine

An important difference between ion-channel receptors and second messenger systems is that the ion-channel receptors produce relatively ___ synaptic actions lasting only milliseconds, whereas second messenger receptors have actions that last from seconds to _______

fast; minutes

In the third step of synaptic transmission (transport)...

for transmitters synthesized in the soma, the vesicles are transported down the axon along the outside of the microtubles. Those transmitters are synthesized in the nerve terminals are already in place and do not need to be transported

As a hormone, the human adrenal gland secretes ___ times more epinephrine than norepinephrine

four

There are ___ common amino acid transmitters

four

Unlike "typical" neurotransmitters, there are no specific receptors for ______

gases

In the PNS, serotonin is found in cells in the _____________ system

gastrointestinal

_____ cells are known to be involved in removing the amino acid transmitters from the synapse

glial

some _____ cells also release neurotransmitters that interact with the neurotransmitter released by the postsynaptic neuron

glial

Zinc has been found in synaptic vesicles that contain the amino acid neurotransmitter ____________

glutamate

Dopamine is released as a hormone by the __________

hypothalamus

Drug effects

increase or decrease synthesis prevent storage prevent transport stimulate transmitter release block transmitter release directly stimulate receptor block the receptor act at autoreceptors block removal of transmitter

________ neurotransmitters play a role in the movement of food through the gastrointestinal system

inhibatory

_________ transmitters keep the CNS from signaling the muscles to contract all at once

inhibitory

Convulsions

involuntary, rhythmic contractions of the muscles throughout the body caused by the chaotic excitatory activity of neurons in the brain

Second messengers are believed to play a role in ________ and ________, as well as ____ adaptive physiological responses

learning;memory;slow

The benzodiazepines bind to one of the GABA receptor types so they are known as ______

mimics

Dopamine (DA)

monoamine transmitter; both an excitatory and an inhibitory neurotransmitter, depending on the receptor - and there are currently 5 known types of dopamine receptors; is found in the CNS and the PNS

Serotonin

monoamine; found in both the CNS and PNS as well as in the bloodstream

Acetylcholine (ACh)

monoamine; the neurotransmitter released at the nerve-muscle junction, which causes muscular contraction

As a neurotransmitter, norepinephrine is ____ common than epinephrine

more

In the second step of synaptic transmission (storage)...

most neurotransmitter molecules are stored in vesicles, which are tiny sacs within a neuron

Parkinson's disease

movement disorder due to too little dopamine in the basal ganglia; begins as a slight tremor called a resting tremor

What are the two general types of cholinergic receptors?

muscarinic and nicotinic

As Parkinson's progresses, the patient develops ________ ______ and has great difficulty initiating movement

muscle rigidity

Most classical neurotransmitters, such as ACh, are synthesized in the _____ ________ whereas other neurotransmitters, such as the peptides, are synthesized in the ____

nerve terminal; cell body

Cholinergic neurons

neurons that release ACh; the most common excitatory transmitter in the PNS

Adrenergic neurons

neurons that release norepinephrine and epinephrine

Many neurons contain more than one type of ___________

neurotransmitter

second messenger system

neurotransmitter can also work indirectly by triggering a chain of chemical reactions that starts with the neurotransmitter interacting with the receptor molecule. Eventually, the last molecule in the sequence causes an ion channel in the membrane to open

In the first step of synaptic transmission (synthesis)...

neurotransmitter molecules are synthesized from precursor chemicals

In the sixth step of synaptic transmission (bind with the autoreceptor)...

neurotransmitters may also bind with a receptor on the presynaptic membrane (the neuron that released it). In this way, the presynaptic neuron receives feedback so that it can adjust the amount of neurotransmitter released

ion-channel receptor

neurotransmitters usually work by directly combining with a receptor, which causes an ion channel to open and let ions flow in or out

Stimulating the autoreceptor would cause the neuron to ___________ the amount of neurotransmitter it was releasing, with the result that it would that synthesize or release ____ of it

overestimate; less

When endorphins are released, they suppress the perception of _____

pain

Curare works by _________ the muscles, including the _________ muscles, which means you stop breathing and die

paralyzing; respiratory

endorphins

peptide neurotransmitter; morphine-like substances produced by the body; the name itself is a contraction of endogenous morphine, which means morphine produced within the body

Both oxytocin and vasopressin are released by the _______ gland

pituitary

Curare causes paralysis by ________ ACh from stimulating the receptors

preventing/blocking

blood-brain barrier

prevents large molecules from moving from the blood vessels into the brain

In many cases, the _______ determines whether a neurotransmitter is excitatory or inhibitory, as well as the degree to which it excites or inhibits the postsynaptic neuron

receptor

The effect of ACh depends on the _______; it is ________ at the nerve-muscle junction, but _________ on the heart

receptor; excitatory; inhibitory

D-serine

released by glial cells known as astrocytes into a synapse where it adjusts the effect the glutamate released by the presynaptic neuron

Serotonin is thought to be one of the tow drugs that cause "_______ _____"

runner's high

Monoamine transmitters

slightly more complicated chemically than the amino acid transmitters; found in both the CNS and the PNS and several play a role in regulating the internal environment

The actions of neuromodulators are ____ and last ______ or _____, suggesting that they could play a role in long term events such as memory

slow; hours;days

Both oxytocin and vasopressin serve as neurotransmitters in the CNS where they are believed to play a role in ______ and ___________ behaviors

social; reproductive

At excitatory synapses, ACh works by opening ______ channels, which lets in those ions causing ___________

sodium; depolarization

Black Widow spider venom does what?

stimulates the release of ACh; causes rigid paralysis followed by flaccid paralysis agonist effect

Nicotine ________ certain ACh receptors, causing the smooth muscles lining the walls of arteries to ______

stimulates; constrict (therefore reducing blood flow)

Which drug blocks Gly receptors? What is the result?

strychnine; convulsions

In the CNS, serotonin is believed to play a role in __________ ___________ and _______; can affect mood as well

temperature regulation; sleep

Why can't oral doses of serotonin enter the brain?

the blood-brain barrier

Amino acids

the building blocks of proteins and amino acid transmitters have simple chemical structures

Acetylcholinesterase (AChE)

the enzyme that breaks down ACh

Runner's high

the euphoric feeling that some athletes report after exercising for 30 minutes or more

Where in the body is NO found?

the intestines and in the nerves going to the erectile tissues of the penis

Catecholamines

the name that norepinephrine, epinephrine and dopamine are called because their chemical structure consists of a "catechol" and "amine" side chain

In the fifth step of synaptic transmission (bind with the receptor)...

the neurotransmitter binds at the postsynaptic receptor site causing an excitatory or inhibitory postsynaptic potential. Nitric oxide, on the other hand, simply diffuses through the membrane of the adjacent neuron

In the last step of synaptic transmission (removal and reuptake)...

the neurotransmitter must be removed from the receptor and the synaptic space to terminate its action. The typical transmitters are either taken back into the presynaptic neuron intact or broken down into their parts and then taken back up.

There are ____ different classes of GABA receptors, each with a number of different subtypes

three

Certain _________ act at GABA receptors, specifically, _____________, such as Valium

tranquilizers; benzodiazepines

There are ___ main types of ACh receptors

two

an axon may release ___ different transmitters simultaneously at the same synapse

two

Norepinephrine and epinephrine

two closely related excitatory neurotransmitters found in both the PNS and CNS. They are also hormones that are released by the inner part of the adrenal glands into the bloodstream

Blocking the autoreceptor would cause the neuron to ___________ its neurotransmitter output thus causing it to produce ____ transmitter

underestimate; more

neuromodulators

what some peptide neurotransmitters appear to be; they do not directly induce signals in other cells, but instead adjust or modulate the sensitivity of the cells to other transmitters

_____, a metal, is the second most abundant trace element in the body

zinc