Summary
Nur 243 Neuropharmacology Summary
- Course
- NUR 243
- Institution
- University Of Rhode Island
This is a comprehensive and detailed summary Neuropharmacology from the book Pharmacology for Nursing Care by Richard A. Lehne.
[Show more]
Content preview
BACKGROUND KNOWLEDGE→the study of drugs that alter processes controlled by the nervous system; drugs
produce effects similar to excitation or suppression of neuronal activity;
The impact of a drug on a neuronally regulated process is dependent on the ability to
directly or indirectly influence receptor activity on target cells
Postsynaptic Cell:
can be another neuron, a muscle cell, or cell w/in secretory gland; if the postsynaptic
cell is another neuron it may increase or decrease firing rate; if it’s a muscle cell it
may contract or relax; if the cell is glandular it may decrease secretion
Receptors:
neurons alter receptor activity by releasing transmitter molecules which diffuse
across the synaptic gap and bind to receptors of the postsynaptic cell; neurons
depend on target cells to have a receptor that the neuron can alter activity
Process of neuron influencing behavior of postsynaptic cell→
1. Axonal conduction: the process of conducting an action potential down the
axon of the neuron; drugs that alter this process are NOT selective (all nerves
along axon will be affected)
→Local Anesthetics: drugs that work by decreasing axonal conduction; produce
non selective inhibition of axonal connection and thereby suppress
transmission in any nerve they reach; valuable but limited indications
***only neuropharmacological drug to not produce their effects by directly or
indirectly altering receptor activity through synaptic transmission
2. Synaptic transmission: the process by which information is carried across the
gap between the neuron and postsynaptic cell; most neuropharmacological
agents/drugs act by altering synaptic transmission; this makes the production
of effects much more selective than axonal conduction
→ axons don’t differ from each other but synapses do; synapses at different
sites have different transmitters
FIVE STEPS OF SYNAPTIC TRANSMISSION:
1. Transmitter Synthesis:
-for the whole process to take place molecules of transmitters must be
present in the nerve terminal; molecules in presynaptic nerve terminal
synthesize the transmitter
-drugs can increase transmitter synthesis (increasing receptor
activation), decrease it (decreasing receptor activation), or create super
transmitters (synthesis of transmitter molecules making it more
effective than transmitter itself)
, -in increased transmitter synthesis storage vesicles will store
abnormally high transmitter amounts; when action potential gets to
axon terminal more transmitters will be released allowing more of
them to be available to receptors at postsynaptic cell increasing
activation of those receptors)
-Some drugs can cause neurons to synthesize transmitter molecules
that have a different structure than normal- these drugs act as
substrates for enzymes in the axon terminal and convert into
→ molecules whose ability to activate receptors is greater
than that of a naturally occurring transmitter at a particular site
ultimately increasing receptor activation
Transmitter Storage:
-one transmitter is synthesized it must be stored until its time of
release; stored in vesicles in axon terminal
-drugs can decrease the storage of transmitters causing a decrease in
receptor activation by interfering with the transmitter storage
Transmitter Release:
-triggered by the arrival of an action potential at the axon terminal;
each action potential causes only a small fraction of all vesicles present
in the terminal to discharge their contents
-drugs can inhibit (decrease receptor activation) or promote (increases
receptor activation) transmitter release
-amphetamines (CNS stimulants) promote transmitter release
-Botulinum toxin inhibits transmitter release
2. Receptor Binding:
-following release, the transmitter molecules diffuse across the
synaptic gap and then undergo reversible binding to receptors of the
postsynaptic cell→ cascade of events altering behavior of postsynaptic
cell
-many drugs act directly at receptors- they can bind to receptors and
cause activation, bind to receptors and block activation, bind to receptor
components and enhance receptor activation by the natural transmitter
at the site
-agonists→ drugs that directly activate receptors (morphine-affects cns,
epinephrine-affects the cardiovascular system, insulin- affects diabetes)
-antagonists→ drugs that prevent receptor activation (naloxone-used to
treat overdose with morphine type drugs, antihistamines, propranolol-
used to treat htn, angina pectoris, and cardiac dysrhythmias)
, - drug that enhances receptor activation→ benzodiazepines: diazepam
and valium- used to treat anxiety, seizure disorders, muscle spasms
Termination of Transmission→ (Removal of transmitter from synaptic gap)
-transmission is terminated by dissociation of transmitter from its receptors then
the free transmitter is removed from the synaptic gap
-drugs can interfere with the termination of transmitter action by blockade of
transmitter reuptake or inhibition of transmitter degradation thereby increasing
receptor activation
1. Reuptake:axon terminals contain pumps that transport transmitter molecules
back into same neuron they were released
2. Enzymatic Degradation: synapse contains large quantities of
transmitter-inactivating enzymes
3. Diffusion: simple diffusion away from synaptic gap; very slow; little
significance
EFFECTS: Synaptic transmission:
-effect on receptor function equivalent to that produced by the natural
neurotransmitter at a particular synapse
-If a drug’s effects mimic effects of natural neurotransmitter the receptor activation
would be increased
-If a drug’s effects were equivalent to reducing the amount of natural transmitter
available for receptor binding the receptor activation would be decreased
-receptor activation can also make a process go slower
→ HR will decrease when the endogenous neurotransmitter acetylcholine
activates cholinergic receptors on the heart (drug that mimics acetylcholine
at receptors on heart will cause the heartbeat to slow)
THE PNS SUBDIVISIONS:
1. Somatic Motor System: controls voluntary movement of muscles
2. Autonomic Nervous System: controls involuntary processes; regulates the
heart, secretory glands (saliva, sweat, gastric, bronchial glands), and smooth
muscle (muscles of the bronchi, blood vessels, urogenital system, and GI tract)
a. Parasympathetic Nervous System:
-“housekeeping”; digestion of food and excretion of wastes, controls vision and
conserves energy by reducing CO
-Drugs used to affect PNS are for their effects on the GI Tract, bladder, and
eye,and occasionally the heart and lungs
-A variety of poisons act by mimicking blocking effects of parasympathetic
stimulation (insecticides, nerve gases, toxic compounds in certain mushrooms
and plants)
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller anyiamgeorge19. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
78998 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now