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Clinical Psychopharmacology Chapter 3 & 4

Terms

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Another name for first messenger molecules
Neurotransmitters
Nerve Cells in human brain? What are they called?
100 billion neurons
Synapses in human brain?
100 trillion
Building blocks for proteins? Method of transmission.
Amino acids via the bloodstream
Responsible for survival of the cell and moment to moment operation?
Amino acids, Oxygen, glucose, and a host of other molecules from capillaries that lie adjacent to the cell.
Dendrites? Purpose? How many dendrites can there be?
Short, branched structures projecting out from cell body. Receive and conduct information to cell body. One or many?
Dendritic spines? Location? Function?
Fine projections. On dendrites. Common locations for synapses.
Axon? Location? Function?
Long fiber extending from cell body. Ends in enlarged structures called terminal boutons. Conducts impulses away from cell body.
Terminal bouton? Location? Function?
Where chemical evens occur. End of axon facing synapse. Delivers neurotransmitters to receptors across synapse (presynaptic to postsynabtic).
Ligands?
A variety of molecules which bind to and activate receptors.
How is change enacted within the cell from a resting state to an action potential?
The activation of excitatory receptors on the dendrites or cell body results in brief change in electrical potential. Ligands bind to and activate these receptors.
Define ligands.
Neurotransmitters, hormones, and certain drugs.
Describe the change from a technical standpoint.
Activation of excitatory receptors on dendrites or cell body. This action potential is converted into a nerve impulse and sends it down the axon.
How does the presynaptic bouton assist this conduction and transmission?
The nerve impulse performs the release of neurotransmitting chemicals into the synapse. The neuron that releases is presynaptic, etc.
Storage containers for neurotransmitter molecules are called?
Vesicles
Where are neurotransmitters manufactured?
In cell body.
Why are neurotrasmitter molecules stored in vesicles?
To protect them from destruction by enzymes that reside in the fluid within the presynaptic terminal bouton.
Describe the passage of neurotransmitters across synapse.
Vesicals migrate toward cell membrane, fuse with it, and create a pore (tiny gateway in cell membrane), discharging contents into synapse.
Describe the capability of neurotransmitters. Ex. Dopamine binds only to dopamine.
They are capable of binding to specific receptors depending on which type of receptor is involved.
Are all neurotransmitters excitatory?
No, some act like a brake when turned on and can reduce nerve cell excitability.
Describe binding properties of molecule seratonin.
It is not itself excitatory or inhibitory. Depnds on which type of seratonin receptor is activated (14 subtypes...most inhibatory, some excitatory...has multiple effects on brain.
Describe the effects of synapse on neurotransmitters.
Some molecules released into synapse, some bind to receptors, some chemically destroyed by enzymes, many reabsorbed into presynaptic neurons.
How are neurotransmitters reabsorbed and stored?
By way of a reuptake transporter pump which repackages them in vesicles(RTP is a protein structure in cell membrane).
How does reuptake inhibition facilitate current antidepressants?
The drug molecule enters the reuptake port and blocks it. the result is that neurotransmitters released into synapse stays longer and has a greater effect on postsynaptic neuron.
Define receptors.
Protein molecules that have been produced in the neuron and are embedded in cell membrane.
Where are receptors located?
Most nerve cells have between 2,000 to 3,000 receptors on the surface of the cell body and dendrites. Many receptors are on surface of cell, but some reside within cell body.
How does one nerve cell influence the functionin of other neurons?
The binding of neurotrasmitters on other receptors.
Did you know?
the absolute # of receptors (brakes and accelerators) which help determine sensitivity/excitability levels of cell are partially determined by genetics (inherent nautre and makeup of cell).
That being so, what about external factors like impact of stressors or drugs?
the regulated systems may alter their functioning chemically or structurally to accomodate to changing environmental circumstances.
what about the body's built-in homeostasis?
There is also a tendancy that after an environmental disturbance has ended the body tries to return to baseline.
How do these neuronal adaptations take place in the body?
Through up-regulation or down-regulation. when body is bombarded by excitatory neurotransmitters chronically, there is often a down regulation in the number and density of down receptors. The converse is true.
How do doctors identify particular types of pathology like depression or psychtropic medication effects?
By assessing the status of receptor density in certain brain regions.
Describe two of the most relevant types of signaling mechanisms out of the five basic types of receptor activities.
1. Ion channel mediated process.
2. G-protein mediated sexcond messenger systems.
What other names refer to these two mechanisms?
1. Ionic
2. Metabolic
Explain Ionic transmission.
When neurotransmitters, durgs or other ligands bind to these receptors, it causes ion channel to open transiently, allowing certain ions (electrically charged molecules) to pass through membrane (permeability). Rapidly occuring
Explain Metabolic transmission.
Most psych meds do not operate via ionic receptors. (excep minor tranqs like benzodiazepines). When ligands bind to these receptors, they operate by activating second messenger systems wtihin cytoplasm of cell (intracellular/biochemical). Slowly occuring. Most psych meds operate this way.
Name the three critical neurtransmitter systems.
Dopamine, serotinin, norepineprine
Draw Presynaptic Membrane and describe.
Action potential opens calcium ion channels and allows Ca++ to enter bouton. Calcium causes vesicles within bouton to blend with membrane and release NT acetylcholine (ACh) into synaptic cleft.
Draw Postsynaptic Membrane and describe.
Two molecules of ACh bind with AChr receptor on membrane of postsynaptic neuron, which allows sodium (Na+) to enter and potassium (K+) to leave cell through channel openings. This activity results in neuronal depolarization.
Memorize Nervous System Handout
Begins with Neurochemical system and ends with Box 5.1 definitions.
Describe the basic parts of the neuron.
Cell body, Axon, dendrites, terminal bouton.
Describe PNS neurons.
PNS made up of nerve cells with long axons and dendrites which carry nerve conduction or signals over a long period of time.
Describe CNS neurons.
No myelin sheath and axons are much shorter. Cells surrounded by glial cells. Some cells act same as macrophages (fights off foreign bodies).
What consitutes the myelin sheath?
Lipid
What is within the lipid sandwich?
Protein: a long chain amino acid, building blocks of carbon compounds and other chemicals for structure and strength.
What are two types of compounds that make up cell wall.
Lipid and Water soluble. Electrolytes, soluble in water, must incorporate active transport to get into the cell. Most meds are lipid soluable. Water soluble compounds require active transport--a factor of blood-brain barrier.
What two methods of conduction and transmitions allows signals to get from one neuron to another?
Action potential and active transport.
True or False. Neurotransmitters tend to be very specific.
True (lock and key theory). Some fit lock but don't turn. Agaonist blocks so that other chemicals cannot get in. Some fit lock and turn it. Cell reacts. the agonist causes it to work on site. Sometimes it causes a process to happen on site (excitatory).
Name the different ways NT happen in brain.
Some manufactured in cell.
Some mitochondria (transforms amino acids)
Some organize compunds and put them together for transmission (golgi app).
Sometimes cell gets lazy (reuptake process). SSRI's prevent this process.
Define enzyme.
Organic catalyst (a compound that helps another ereaction to happen when these other compounds are broken down or built).
Memorize neurotransmitters in handhout.
These are the ones we'll be considering this semester.
What's a general term for a compound that fits a receptor site?
Ligand (key that fits the lock).
Define bioavailability.
the amount of drug that gets to the brain after it has broken down in the body.
IV
Intravenous...quick bioavailability
IM
Intramuscular, how fast will be determined by how big the molexcules are, whether they are lipid or water soluble.
DEPOT
Meds injected IM with oil to keep it at a certain level in the body over a longer period of time. Certain neuroleptics injected this way.
SUBCU
Subcutaneous. Few psychotropic meds administered this way. Area between epidermis and deep muscle tissue. Absorbed in slow way.
Sublingual
Under tongue. Absorbed in mucous membranes, very rapid into blood stream (nitro glycerin example). Also Zyprexa. Use when you must be sure pt. takes the drug.
Nasally.
Stadol for migraines is the one legitimate drug taken in this form.
First pass defined.
Amt. of blood metabolized before reaching bloodstream.
Steady state.
When concentrations of a medication in bloodstream have reached a plateau. SS occurs when amt. of meds administered is equal to amt. being eliminated.
Half-life.
Amount of time required for serum concentration to be reduced by 50 percent.
Versed?
Mild sedative. Quick acting, short half-life.
Window of effectiveness.
Can be broad or narrow. Lithium has narrow window. Depacote also has narrow window. Give only enough to work without going over.
Explain one of the things that can happen with protein binding.
You might add another med that has a greater affinity. so the protein drops the one and picks up another. So, you can have a chem. bound to a protein and another drug comes in and releases it.
Metabolites?
What's left over after compounds are broken down. Serum blood screening will measure actual levels of drug in body.
Blood brain barrier
System of structures and functions in brain that controls what gets in and out.
1. BBB - Structural
Capillaries and blood vessels in brain are different from body. The cell ways are different. Capillaries are tightly packed and closely cemented. They do not let things in and out very easily.
2. BBB - Structural
Glial cells surround capillary in densely packed coverings. Form more of a barrier between blood and brain (astrocites).
3. BBB - Physiologic
Physiological elements to blook brain barrier (lipid soluble). Only lipid soluble gets in.
4. BBB - Metabolic
Enzymes, chemical structures. Parkinson's disease caused by depletion of dopamine in basal ganglia in brain (involuntary movements to help keep them smooth). Levidopa can get into cell because it has ability to attach to lipid and protein on external side of cell and be taken in and transformed into dopamine.

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