Main Discussion Post: Week 2

Agonist to Antagonist Spectrum of Action

The mechanisms of psychopharmacologic medications is to work at the sites of neurotransmission and there effects are based on a spectrum of agonist to an antagonist. An agonist is a molecule that is similar to the effects of a neurotransmitter by binding and stimulating the receptor site to produce a response (Berg & Clarke, 2018). An antagonist opposes the outcome of the agonist, which blocks the action of neurotransmission. Antagonists are referred to as mediators of therapeutic actions in psychiatric disorders and the cause of undesirable effects (Berg & Clarke, 2018). The spectrum of agonist to antagonist consist of a full agonist, partial agonist, silent antagonist, and inverse agonists. The full agonist allows the receptor to fully open the ion channel, which provides signal transduction to occur (Berg & Clarke, 2018). The partial agonist occurs when the receptor has a resting state. The silent antagonist returns the receptor to a resting state. Inverse agonist cause receptor change and the closing of ion channels (Berg & Clarke, 2018). Depending on where a specific psychopharmacological drug is located on the agonist to antagonist spectrum determines the interaction with the targeted receptor.

G Couple Proteins and Ion Gated Channels

G couple proteins represent the most abundant family membrane proteins in the human genome, that is activated by a spectrum of structurally diverse ligands (Li et al., 2016). There are seven different protein segments that transmit signals for binding sites for neurotransmitters (Li et al., 2016). This process allows for therapeutic drug interations to occur. Once the drugs attach to the receptor sites, a full of partial blocking function of neurotransmitters occurs. The molecular changes can be affected by drug actions and cause changes or determine which enzymes, receptors, or ion channels are modified by neurotransmission (Li et al., 2016). Ion gated channels are electrically controlled. Unlike ions, G couple proteins can diffuse through the membrane, which can change a cells behavior and ions can not diffuse due to their charge (Li et al., 2016). A comparison of both ion channels and G protein linked receptors is the agonist spectrum. Medications that change the flow of ions can cause a clinical effect, unlike drugs that target G protein linked receptor sites, which take a longer timeframe (Li et al., 2016).

Epigenetics

The role of epigenetics determines if some genes will become a specific RNA and protein, or if it will turn off, based on the structure of chromatin, neurotransmission, genes, drugs, or the environment (Weinhold, 2017). All of these factors affect the brain in a variety of ways and can result in ineffective information processing. Ineffective information processing can increase the risk of psychiatric disorders. Epigenetics also affect the way a drug work for different individuals. Drugs may not be designed to be specific to a particular gene or protein subtype. The drugs may have to be more broad-acting (Weinhold, 2017).

Prescribing

An example of a case in which a psychiatric mental health nurse practitioner must be aware of a medication action was for a patient with a diagnosis of Bipolar. The drug of choice was Lithium, which is a mood stabilizer. Lithium has a lot of potential side effects both minor and major. It is the responsibility of the health care provider to thoroughly explain drug side effects and the expected action of the drug. The nurse practitioner explained to the patient the need for routine blood work to ensure compliance and monitor Lithium levels. The patient was required to receive weekly labs and medication management to prevent Lithium toxicity. It is important to be aware of the mechanism of action of medications to know when and what effects will take place. Lithium acutely stimulates the NMDA receptor, increasing glutamate availability in the postsynaptic neuron (“Lithium,” 2020). As a future psychiatric nurse practitioner I can utilize the content of this discussion post to impact the prescribing of medication to my patients. The information has afforded me a basis of knowledge on pathophysiology and how medication impact the central nervous system. The data also teaches me that in addition to writing prescriptions, it is vital to have background information regarding the effects drugs have on receptor sites, if the agents act as a neurotransmitter or agonist, or if the agents block the receptor sites (Berg & Clarke, 2018).

 References

Berg, K. A., & Clarke, W. P. (2018). Making sense of pharmacology: Inverse agonism and functional selectivity. International Journal of

             Neuropsychopharmacology, 21(10), 962–977. https://doi.org/10.1093/ijnp/pyy071

Li, S., Wong, A. C., & Liu, F. (2016). Ligand-gated ion channel interacting proteins and their role in neuroprotection. Frontiers in Cellular

             Neuroscience, 8. https://doi.org/10.3389/fncel.2014.00125

Lithium. (2020). Reactions Weekly, 1810(1), 130–130. https://doi.org/10.1007/s40278-020-80150-1

Weinhold, B. (2017). Epigenetics: The science of change. Environmental Health Perspectives, 114(3). https://doi.org/10.1289/ehp.114-

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Discussion: Foundational Neuroscience

As a psychiatric nurse practitioner, it is essential for you to have a strong background in foundational neuroscience. In order to diagnose and treat patients, you must not only understand the pathophysiology of psychiatric disorders but also how medications for these disorders impact the central nervous system. These concepts of foundational neuroscience can be challenging to understand. Therefore, this Discussion is designed to encourage you to think through these concepts, develop a rationale for your thinking, and deepen your understanding by interacting with your colleagues.

Photo Credit: Getty Images/Cultura RF

For this Discussion, review the Learning Resources and reflect on the concepts of foundational neuroscience as they might apply to your role as the psychiatric mental health nurse practitioner in prescribing medications for patients.

By Day 3 of Week 2

Post a response to each of the following:

  1. Explain the agonist-to-antagonist spectrum of action of psychopharmacologic agents, including how partial and inverse agonist functionality may impact the efficacy of psychopharmacologic treatments.
  2. Compare and contrast the actions of g couple proteins and ion gated channels.
  3. Explain how the role of epigenetics may contribute to pharmacologic action.
  4. Explain how this information may impact the way you prescribe medications to patients. Include a specific example of a situation or case with a patient in which the psychiatric mental health nurse practitioner must be aware of the medication’s action.

Read a selection of your colleagues’ responses.

By Day 6 of Week 2

Respond to at least two of your colleagues on two different days in one of the following ways:

  • If your colleagues’ posts influenced your understanding of these concepts, be sure to share how and why. Include additional insights you gained.
  • If you think your colleagues might have misunderstood these concepts, offer your alternative perspective and be sure to provide an explanation for them. Include resources to support your perspective.

Note: For this Discussion, you are required to complete your initial post before you will be able to view and respond to your colleagues’ postings. Begin by clicking on the “Post to Discussion Question” link and then select “Create Thread” to complete your initial post. Remember, once you click on Submit, you cannot delete or edit your own posts, and you cannot post anonymously. Please check your post carefully before clicking on Submit!

You have done an excellent job of summarizing the fundamental neuroscience terms and functions. I want to elaborate more on the topic of epigenetics. Epigenetics explains the changes that affect the phenotypes without changes in genotypes. It studies inheritable but reversible changes in genes’ expression without modifying primary DNA sequences (Lundstorm, 2015). Epigenetics plays a role in psychiatric illness that occurs in response to environmental stimuli such as chronic stress and drug abuse. Major depressive disorder (MDD), drug addiction, and schizophrenia (Mahgoub & Monteggia, 2013). Therefore, a better understanding of how epigenetic mechanisms underlie psychiatric disorders may help characterize how these modifications impact specific genes that may contribute to these disorders.

 

Reference

 

Lundstorm, K. (2015). What is the potential of epigenetics. Future Medical Chemistry, 7(3), 239-242. doi:10.4155/FMC.15.2

 

Mahgoub, M., & Monteggia, L. M. (2013). Epigenetics and psychiatry. Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 10(4), 734–741. https://doi.org/10.1007/s13311-013-0213-6