NURS 520 psychopharmacology Module 2 Discussion: Chemical Neurotransmission

Modern psychopharmacology is largely the story of chemical neurotransmission. One must be fluent in the language and principles of chemical neurotransmission to:

• Understand the actions of drugs on the brain,
• Grasp the impact of diseases upon the central nervous system,
• Interpret the behavioral consequences of psychiatric medicines.

After studying discuss the following:

• When a cell is stimulated or polarized, it fires an action potential. Explain the process and how neurotransmitters are dispersed to other neighboring cells across the synapse.
• Explain the concept of a drug’s half-life.

Submission Instructions:

• Your initial post should be at least 500 words, formatted and cited in current APA style with support from at least 2 academic sources.  Your initial post is worth 8 points.
• You should respond to at least two of your peers by extending, refuting/correcting, or adding additional nuance to their posts. Your reply posts are worth 2 points (1 point per response.)
• All replies must be constructive and use literature where possible.
• Please post your initial response by 11:59 PM ET Thursday, and comment on the posts of two classmates by 11:59 PM ET Sunday.
• Late work policies, expectations regarding proper citations, acceptable means of responding to peer feedback, and other expectations are at the discretion of the instructor.
• You can expect feedback from the instructor within 48 to 72 hours from the Sunday due date.

NURS 520 psychopharmacology Module 2 Discussion: Chemical Neurotransmission Sample Essay

Week 2

Neurotransmitters

An action potential is the communication of the neurons through electrical signals that naturally move from the cell body down to the axon then to the axon terminals. For this took take place enough receptors have to be stimulated together which creates an electrical impulse the end result is action potential. As Sinacola states “A neuron has four basic parts the stoma, dendrites, axon, and terminal buttons” (Sinacola et al., 2020 Pg.4). Medications can activate the neurons through a process called exogenous reaction that causes the activation of the neurons. Exogenous is basically the route of introduction into the body was made outside of the body such as medications that are taken orally. As Sinacola states “Receptor sites on the postsynaptic membranes of dendrites are the most common target of medication that can activate their respective cells” (Sinacola et al., 2020 Pg.5).  Incoming signals come through the dendrites outgoing signals travel by the axon to the nerve terminal. The action potential is initiated as an outgoing signal on the axon’s neuron sending an electrical signal along the axon. The sodium channels are activated the gated sodium channel opens when it reaches -55 mv voltage and activates the gated sodium channels when they are open sodium ions move into the cell and changes the voltage +30 mv with the voltage in the cell reaches 30 mv the sodium channel gates close. Basically, depolarization is taking place making inside the cell positive as it is moving down the axon towards the axon terminal. The action potential moves all the way down the axon to the terminal buttons. As Sinacola states “Once it is reached the terminal button. Action potential causes vesicles to fuse with presynaptic membrane resulting in the calcium ions to release vesicles of neurotransmitters into synapse” (Sinacola et al., 2020 Pg.8).

Half-Life

The concept of the half-life of a drug is to determine the daily dosage of the medication regimen and keep the concentration of the medication at desired levels to achieve a therapeutic effect with minimal side effects. As Smith states “A half-life of 12–48 h is generally ideal for once-daily dosing of oral drugs. If the half-life is too short, it may require more frequent dosing in order to maintain desired exposures and avoid unnecessarily high peak concentrations (Smith et al., 2017). When considering the half-life of a drug other factors should be considered such as the patient’s age, current health status, weight, existing comorbidities such as congestive heart failure, kidney disease, and liver disease. Other factors to take into consideration of a medications’ half-life are the drug clearance and volume of distribution. For example, if an individual has kidney disease present the drug will not be excreted as efficiently. As Sinicola states “A patient with kidney dysfunction may not excrete the drug normally, and the concentration may become elevated and toxic” (Sinacola et al., 2020 Pg.15). Volume distribution can be altered if a patient has congestive heart failure and is carrying excess fluids in the body. As Smith states” Volume of distribution is one of the most important pharmacokinetic properties of a drug candidate. It is a major determinant of half-life and dosing frequency of a drug” (Smith et al., 2017).

References

Sinacola, R. S., Strickland, T. P., & Wyner, J. D. (2020). Basic Psychopharmacology for Mental Health Professionals (3rd ed.). Pearson.

Smith, D. A., Beaumont, K., Maurer, T. S., & Di, L. (2017). Relevance of Half-Life in Drug Design. Journal of Medicinal Chemistry, 61(10), 4273–4282. https://doi.org/10.1021/acs.jmedchem.7b00969

Zhang, Y.-H., Chu, C., Wang, S., Chen, L., Lu, J., Kong, X. Y., Huang, T., Li, H. P., & Cai, Y.-D. (2016). The use of Gene Ontology Term and Kegg Pathway Enrichment for Analysis of Drug Half-Life. PLOS ONE, 11(10). https://doi.org/10.1371/journal.pone.0165496 (Links to an external site.)

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