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Nurs 8022 case study 1

Nurs 8022 case study 1

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NURS 8022 Case Study #1

1. Lidocaine and local anesthetics agents block action potentials in nerve fibers

by binding to specific ion channels. At low concentration, these drugs

decrease the rate of the rise of the upstroke of the AP. At higher

concentrations, they prevent occurrence of the AP altogether. Based on this

information and your knowledge of the ionic basis of the action potential,

which ion channel would you conclude is blocked by Lidocaine? Explain how

these ion channels are important.

Lidocaine as well as anesthesia causes a block in the Na + channels - When

Lidocaine and anesthesia are administered at low concentrations sodium

poses a slower upstroke thus leading to a slower action potential. Hence,

when Lidocaine and anesthesia are administered at a higher rate there is a

total blockade of the upstroke capabilities causing no action potential.

Investigations during the last few decades presented evidence implicating the

sodium (Na

) channel protein as a target for specific, clinically important, local

anesthetic effects on mammalian neurons. At clinically relevant concentrations

local anesthetics can also affect potassium (K

) and calcium (Ca

) channels, which

might help explain some of their side‐effects (2002).

https://academic.oup.com/bja/article/89/1/52/256293

When Lidocaine/anesthesia (stimulus) is administered in high dosages the

threshold of the Na+ is met and in higher dosages there causes an upstroke

during depolarization until the action potential is met at the equilibrium. At

the peak of the action potential when the equilibrium is met, the Na+

channels open and enters the cells. Respectively, positive charges repel each

other. At the peak, the voltage gated potassium reaches a peak where the

potassium gates open up and potassium leaves the cell which is known as

repolarization. Potassium leaves the cell during repolarization towards it’s

resting membrane potential.

2. Based on your knowledge of how nerve action potentials are propagated,

how would you expect lidocaine to alter the conduction of the AP along a

nerve fiber?

Action potentials are propagated by starting at the local regions to the

depolarization regions. This upstroke at the depolarized regions triggers the

opening gates and inward flow of the Na+ of the upstroke action potential.

The stimulus of lidocaine thus blocks the voltage gate of the Na+. When the

voltage gate of Na+ is blocked, the inward current of the Na+ does not

happen thus this is the propagation of the action potential that transpires

from depolarization of the inward current in prevented. Small positive

shifts of the membrane potential, beyond a threshold causes

channels to move open. Channel opening results in a rapid

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NURS 8022 Case Study #1 1. Lidocaine and local anesthetics agents block action potentials in nerve fibers by binding to specific ion channels. At low concentration, these drugs decrease the rate of the rise of the upstroke of the AP. At higher concentrations, they prevent occurrence of the AP altogether. Based on this information and your knowledge of the ionic basis of the action potential, which ion channel would you conclude is blocked by Lidocaine? Explain how these ion channels are important. Lidocaine as well as anesthesia causes a block in the Na + channels - When Lidocaine and anesthes ...
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