Foundational Neuroscience NURS 6630
Foundational Neuroscience NURS 6630
A Sample Answer For the Assignment: Foundational Neuroscience NURS 6630
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.
The agonist spectrum can be explained best as a scale from agonist to inverse agonist; with natural neurotransmitters being an agonist or drugs that stimulate the receptors for that action. Partial agonist follows the agonist because of drugs that stimulate the same receptors on a lower gradation of the spectrum (Stahl, 2021). The next level on the spectrum is the antagonist blocking the action of the agonist (Stahl, 2021).
The final function is the inverse agonist has two behaviors: (1) block the agonist, and (2) lower the level of activity below the starting point in absence of an agonist (Stahl, 2021). The best way to explain a partial agonist is to present a medication used in the treatment of depression. Vilazodone is a serotonin reuptake inhibitor, which causes a rise in serotonin at the synaptic cleft by preventing the re-uptake of serotonin at the presynaptic axon terminal (Comprodon & Roffman, 2016).
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However, Vilazodone also signals the 5HT1A presynaptic receptors and causes a decrease in the production of serotonin acting as a partial agonist (Baumgartnera et al., 2020). The outcome of partial and inverse agonists can be a marked increase or decrease in the concentration of a drug from the inhibition or excitation of the drug’s receptors (Comprodon & Roffman, 2016).
2. Compare and contrast the actions of g couple proteins and ion gated channels.
Two of the four methods of signal transduction involve neurotransmitters rather than hormones or neurotrophins (Stahl, 2021). G-coupled proteins and ion-gated channels are similar because they are stimulated by drugs that cause neurotransmitters to activate genes inside of the cell when a phosphate is added to the cAMP protein (Stahl, 2021).
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Although they have similarities, the first, G-coupled proteins, cause a slow neuronal effect as a result of its action with cAMP and protein kinase A (Comprodon & Roffman, 2016). The second, ion-gated channels, cause a rapid neuronal effect on the membrane potential as a result of calcium and a kinase called CaMK (Comprodon & Roffman, 2016).
3. Explain how the role of epigenetics may contribute to pharmacologic action.
Epigenetics describes the heritable action of DNA when gene function changes from one generation to the next because of the influence of the external milieu (Comprodon & Roffman, 2016). DNA can be affected by experiences triggering phenotype modifications rather than genotype changes medications (Quevedo et al., 2022). Stress, such as physical abuse in children, is positively correlated with the development of borderline personality disorder (Comprodon & Roffman, 2016; Quevedo et al., 2022).
The downstream effect of neuroplasticity can result in changes at the genetic level resulting in DNA sequencing variations (Quevedo et al., 2022). Once the chromatin’s structure is modified, the encoding of proteins may alter the original behavior of synaptic uptake of drugs causing changes of pharmacological action, such as enhanced or diminished responses to medications (Quevedo et al., 2022). The increased or decreased action at the receptor site may enhance or inhibit the action of a drug and cause an unexpected outcome.
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.
Epigenetic changes are crucial to understand when prescribing medications to patients who have suffered trauma (child abuse, substance misuse, malnutrition, etc.) resulting in DNA silencing or activation (Comprodon & Roffman, 2016). The stress response to physical, emotional, or sexual abuse can cause increased DNA methylation in various tissues in the body, namely blood, saliva, and brain tissue (Quevedo et al., 2022).
Therefore, the PMHNP should be well versed in the biomechanics of a medication for appropriate and effective prescribing. One example is the higher reactivity of the HPA axis to adverse childhood experiences stimulating Corticotropin Releasing Hormone (CRH), which triggers the release of adrenocorticotropin hormone from the pituitary gland (Quevedo et al., 2022). A corticotropin releasing hormone antagonist may be ineffective if one’s mental health is severely affected by a history of abuse. Therefore, the PMHNP should consider an alternative medication to a CRH antagonist.
References
Baumgartnera, K., Doeringb, M., & Schwarz, E. (2020). Vilazodone poisoning: A systematic review. Clinical Toxicology, 58(5), 360–367. https://doi.org/10.1080/15563650.2019.1691221
Camprodon, J. A., & Roffman, J. L. (2016). Psychiatric neuroscience: Incorporating pathophysiology into clinical case formulation. In T. A. Stern, M. Favo, T. E. Wilens, & J. F. Rosenbaum. (Eds.), Massachusetts General Hospital Psychopharmacology and Neurotherapeutics (pp. 1–19). Elsevier.
Quevedo, Y., Booij, L., Herrera, L., Hernández, C., & Jiménez, J. P. (2022). Potential epigenetic mechanisms in psychotherapy: A pilot study on DNA methylation and mentalization change in borderline personality disorder. Frontiers in Human Neuroscience. https://doi.org/10.3389/fnhum.2022.955005
Neuroscience is the scientific study of the human central nervous system to understand the brain’s dysfunction that can lead to disease, mental disorders, and physical impairment (Karmarkar & Plassmann, 2019). The complex design of a neuron is the basic understanding of communication by sending impulses to other body organs.
The brain controls human behavior and the functions of body organs. The anatomy and physiology of the brain help understand the part of the brain affected by mental illness. For example, poor concentration and cognitive skills dysfunction is the forebrain pathology. Additionally, one can understand the mode of action of psychopharmacology. For example, antidepressants may function by inhibiting the serotonin or epinephrine receptors.
An Agonist-To-Antagonist Spectrum of Action and How Partial and Inverse Agonists Influence Psychopharmacologic
An antagonist binds at the receptors by blocking any event of an agonist, hence, blocking the biological response. For example, naloxone is a competitive opioid antagonist and has no effects with opioid co-administration (Gicquelais, et al, 2019). An agonist binds to a receptor causing activation of the receptor, hence, the biological response.
A partial agonist activates the receptors partially with lesser effect on the brain. For example, buprenorphine is a partial agonist, and therefore, an antagonist may block its opioid function without activating its receptors. An inverse receptor binds with constitutively active receptors and inhibits receptor activity by exerting opposite pharmacological effects that suppress spontaneous receptor signaling.
Comparison between Actions of G Couple Proteins and Ion Gated Channels
G coupled proteins GPCRs are integral membrane proteins that convert extracellular responses to hormones, neurotransmitters, olfaction, and taste signals. The GPCRs work by binding to the hormones, neurotransmitters, and growth factors to initiate a cellular response. The three types of G-couple receptors are alpha, beta, and gamma, in which the ligands bind and activate (Yudin & Rohacs 2019).
Ion gated channels are integral membrane proteins of excitable cells that allow a flux of ions to pass only under defined circumstances. These channels are voltage-gated sodium channel neurons and ligand-dated acetylcholine receptors of the cholinergic synapses. The ion gated channel pull and bonds to the agonist changing the protein while g coupled proteins are used by the cells to convert intracellular signals into responses.
The Role of Epigenetics In the Pharmacologic Action
Epigenetics regulate gene activity by switching off the gene activity or activating the gene activity. Epigenetics plays a role in the phenotypic activity of the cell in diseases such as cancer and neurodegenerative disorders such as Alzheimer’s disease. Epigenetics modify gene expressions after drug administration to counteract the disease states in humans. Epigenetics proves its effectiveness in treating psychiatric and neurodegenerative disorders to its ability to modify gene expressions.
The Significance of the Information to Psychiatric Mental Health Nurse Practitioner
A psychiatric mental health nurse practitioner should have basic knowledge of the concepts of foundational neuroscience. Understanding the function of agonists, inverse and partial agonists, and antagonists prevent co-administration of drugs that agonize and antagonize the same receptors. For example, in treating a patient with a depressive mood disorder, prescribing antipsychotics such as fluphenazine worsens the depressive mood because it antagonizes the dopaminergic D1 and D2 receptors depressing the release of the hypothalamic hormone.
References
Gicquelais, R. E., Bohnert, A. S., Thomas, L., & Foxman, B. (2020). Opioid agonist and antagonist use and the gut microbiota: associations among people in addiction treatment. Scientific reports, 10(1), 1-11. https://doi.org/10.1038/s41598-020-76570-9
Karmarkar, U. R., & Plassmann, H. (2019). Consumer neuroscience: Past, present, and future. Organizational Research Methods, 22(1), 174-195.
Yudin, Y., & Rohacs, T. (2019). The G‐protein‐biased agents PZM21 and TRV130 are partial agonists of μ‐opioid receptor‐mediated signalling to ion channels. British journal of pharmacology, 176(17), 3110-3125. https://doi.org/10.1111/bph.14702
RE: Initial post
I really enjoyed reading your article, it was very informative. However, in addition to your points about the agonist-antagonist spectrum, I will like to share additional insight I found interesting too.
According to Berg and Clarke (2018), Agonists have intrinsic efficacy (the ability to increase the activity of a receptor), and inverse agonists are said to have negative intrinsic efficacy (the ability to decrease the activity of a receptor). Just as agonist intrinsic efficacy for a receptor varies with the structure of the agonist (resulting in strong agonists and weaker [partial] agonists), inverse agonists also have different degrees of negative intrinsic efficacy, resulting in strong and weak (partial) inverse agonists.
Inverse agonists are ligands that selectively bind to the inactive state of the receptor (Kenakin, 2017). If any receptor happens to be in an active state spontaneously, then an inverse agonist will reverse the resultant constitutive activity.
However, the main pharmacological effect of inverse agonists is receptor antagonism, that is, inverse agonists will block the effect of agonists and the effect on constitutive activity is only relevant if the system is spontaneously active (Kenakin, 2017). There is a property of inverse agonists that may be therapeutically relevant in nonconstitutively active systems (Kenakin, 2017).
References
Berg, K. A., & Clarke, W. P. (2018). Making sense of pharmacology: Inverse agonism and functional selectivity. The international journal of neuropsychopharmacology, 21(10), 962–977. https://doi.org/10.1093/ijnp/pyy071
Kenakin, T. P. (2017). Pharmacology in Drug Discovery and Development (Second Edition). ScienceDirect. Retrieved June 10, 2022, from https://doi.org/10.1016/B978-0-12-803752-2.00004-1
As a psychiatric and mental health 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:
- 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.
- Compare and contrast the actions of g couple proteins and ion gated channels.
- Explain how the role of epigenetics may contribute to pharmacologic action.
- 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!
FOUNDATIONAL NEUROSCIENCE
As a psychiatric and mental health 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.
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.
RESOURCES
Be sure to review the Learning Resources before completing this activity.
Click the weekly resources link to access the resources.
BY DAY 3 OF WEEK 2
Post a response to each of the following:
- 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.
- Compare and contrast the actions of g couple proteins and ion gated channels.
- Explain how the role of epigenetics may contribute to pharmacologic action.
- 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.
The agonist-to-antagonist spectrum of action of psychopharmacologic agents
Great post-Mfon, I agree with you that Psychopharmacologic agents can function as agonists, antagonists, partial agonists, or inverse agonists, significantly influencing the effectiveness of psychopharmacological therapies.
Agonists bind to receptors and activate them to act, while antagonist acts by interfering with the function of the receptors by binding and immobilizing their activities. Examples of full opioid agonists are oxycodone, morphine, methadone, heroin, and others. At the same time, examples of antagonists are naloxone (Narcan) and Naltrexone.
From personal experience seeing a patient that overdosed on Fentanyl unresponsive and with practically no pulse comes to life with the administration of Narcan is a rewarding experience to behold; how this antagonistic drug inactivates the effects of fentanyl and restores the functionality of the patient.
As the name implies, partial agonists only partially act on the receptor and moderately affect it. Partial agonists are used to control and monitoring pending cases example, Buprenorphine is a partial opium antagonist that helps relieve withdrawals and help stop cravings (Zamolodchikova et al., 2021). Inverse agonists, like you correctly mentioned, reduce neurotransmitters’ receptor function by attaching them, reducing efficacy, and producing a negative impact.
Actions of G-couple proteins and ion-gated channels.
G-couple proteins and channels are located in the plasma membrane and are unique. G- couple proteins utilize ion-specific ion channels that are directly activated by other proteins: g-protein coupled receptors, as mentioned before, do help medicate most of the body’s physiological responses to neurotransmitters and other stimulants (Ligand-Gated Ion Channels, 2011). Ion-gated Channels (IGCs) passively allow selected ions across the plasma membrane; only the selected membrane can pass through the pore and then bind to the neurotransmitter. (Ligand-Gated Ion Channels, 2011)
Role of epigenetics
Epigenetics, as you correctly defined it, is essential in utilizing and factoring in genetic and DNA components to produce drugs tailored to each patient’s need accurately: Drugs are made to target specific receptors and effects a change in the genetic expression to archive specific outcomes (Stefanska & MacEwan, 2015).
Professionals like NPs have known this psychopharmacologic agent to treat patients with mental health issues because pharmacologic enzymes, as you rightly pointed out, can epigenetically landscape and gene expression profiles. With in-depth knowledge of epigenesis, for example, an NP will know that Librium helps in curtailing alcohol withdrawal and should be able to taper based on the patient’s needs.
References
Ligand-Gated Ion Channels. Br J Pharmacol. 2011 Nov;164(Suppl 1): S115–35. doi: 10.1111/j.1476-5381.2011.01649_4.x. PMCID: PMC3315629.
Stefanska B, MacEwan DJ. Epigenetics and pharmacology. Br J Pharmacol. 2015 Jun;172(11):2701-4. doi 10.1111/bph.13136. PMID: 25966315; PMCID: PMC4439868
Zamolodchikova TS, Tolpygo SM, Kotov AV. From Agonist to Antagonist: Modulation of the Physiological Action of Angiotensins by Protein Conjugation-Hemodynamics and Behavior. Front Pharmacol. 2021 Nov 3;12:772217. Doi: 10.3389/fphar.2021.772217. PMID: 34803713; PMCID: PMC8595096.
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 Reply button to complete your initial post. Remember, once you click on Post Reply, you cannot delete or edit your own posts and you cannot post anonymously. Please check your post carefully before clicking on Post Reply!
Neuroscience and Prescription
Agonists and antagonists are critical players in pharmacology and, generally, in the human body. Agonist binds to a receptor, thus altering its state and producing an appropriate response (Patinote et al.,2020). They are considered the prime movers responsible for creating a specific movement. On the other hand, the antagonists are ligands that prevent the agonist from binding to a receptor, preventing its effects (Patinote et al.,2020).
They do not by themselves contain pharmacological actions that are mediated by the receptors. Generally, this means that the agonists and antagonists act in different directions, whereby the agonists introduce an action while the antagonist opposes it. The agonist works with the muscles while the antagonists work against them. Furthermore, the agonist alters the functionality of the activities of the receptors, while the antagonists do not alter the activities of the receptors despite their binding to the receptor.
Moreover, the partial agonists cannot produce the maximal response of the tissue can regardless of whether they have the same number of receptors as full agonists. Therefore, a certain level of binding is where the partial agonist can bind the receptors without consequently producing additional effects (Patinote et al.,2020). Nevertheless, doing so may hinder the activities of other agonists, thus being seen as antagonists.
Therefore, this mixture of actions is referred to as a partial agonist. Moreover, an inverse agonist binds to a receptor and produces a response different from that of the corresponding agonist (Patinote et al.,2020). When the agonist increases the activity mediated by a receptor, the inverse agonist decreases it.
The actions of G couple proteins and the ion-gated channels share similarities and differences. They are both considered transmembrane us proteins with ligand binding sites and have an effect on the cytoplasmic (Hu et al.,2021). In addition, they both, to some extent, react to the ligand, where they change their shape.
The differences are that the G Protein receptors have a single polypeptide tied over the membrane. On the other hand, the ion channel has pores open and close when ligand binding occurs. Another difference is that the G protein-coupled receptors often interact highly with various proteins for an intra