NURS 6630 Discussion Reflect On Concepts Of Foundational Neuroscience
NURS 6630 Discussion Reflect On Concepts Of Foundational Neuroscience
NURS 6630 Discussion Reflect On Concepts Of Foundational Neuroscience
The Agonist-To-Antagonist Spectrum of Action of Psychopharmacologic Agents
Agonists are drugs that stimulate receptors similar to natural neurotransmitters, while antagonists are drugs that block the actions of a natural neurotransmitter at its receptor. True antagonists only apply their actions in the presence of an agonist since they have no intrinsic activity of their own in the absence of an agonist (Stahl & Stahl, 2013). Drugs acting at a receptor occur in a spectrum from full agonist to antagonist to an inverse agonist. Antagonists block the actions of everything in the agonist spectrum.
At one end of the agonist-to-antagonist spectrum, there is the full agonist, which produces the same degree of physiologic receptor-mediated response as the natural neurotransmitter agonist itself (Stahl & Stahl, 2013). At the other end of the spectrum is a full inverse agonist, which in concept does oppose the agonist. In the middle of the spectrum is the antagonist, which blocks the effects of all participants in the spectrum but has no properties of its own in altering the ion channel (Stahl & Stahl, 2013). Thus, the agonist-to-antagonist spectrum goes from full agonist to partial agonist to antagonist to partial inverse agonist to full inverse agonist.
Compare and Contrast the Actions of G Couple Proteins and Ion Gated Channels
Both G couple proteins and ion-gated channels are involved in the opening and closing of postsynaptic ion channels. However, the two accomplish this in different ways. Ion-gated channels are directly linked to ion channels and contain two functional domains. An extracellular site binds neurotransmitters and a membrane-spanning domain that forms an ion channel and thus combines transmitter-binding and channel functions into a single molecular entity (Wulff & Christophersen, 2015). On the other hand, G-protein-coupled receptors do not have ion channels as part of their structure. They thus affect channels by activating intermediate molecules called G-proteins (Johnson & Lovinger, 2016). G-protein-coupled receptors act by dissociating from the receptor and interacting directly with ion channels or bind to other effector proteins, such as enzymes, that form intracellular messengers that open or close ion channels.
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 mental health nurse practitioner, it is essential for you to have a strong background in foundational neuroscience. In order to diagnose and treat clients, 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.
Required Readings
Note: All Stahl resources can be accessed through the Library using this link. This link will take you to a log-in page for the Library. Once you log into the library, the Stahl website will appear.
Stahl, S. M. (2013). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications (4th ed.). New York, NY: Cambridge University Press *Preface, pp. ix–x
Note: To access the following chapters, click on the Essential Psychopharmacology, 4th ed tab on the Stahl Online website and select the appropriate chapter. Be sure to read all sections on the left navigation bar for each chapter.
Chapter 1, “Chemical Neurotransmission”
Chapter 2, “Transporters, Receptors, and Enzymes as Targets of Psychopharmacologic Drug Action”
Chapter 3, “Ion Channels as Targets of Psychopharmacologic Drug Action”
Document: Midterm Exam Study Guide (PDF)
Document: Final Exam Study Guide (PDF)
Also Read: NURS 6053 Review of current Healthcare Issues
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NURS 6630 Discussion Reflect On Concepts Of Foundational Neuroscience
Required Media
Laureate Education (Producer). (2016i). Introduction to psychopharmacology [Video file]. Baltimore, MD: Author.
Note: The approximate length of this media piece is 3 minutes.
Accessible player
Optional Resources
Laureate Education (Producer). (2009). Pathopharmacology: Disorders of the nervous system: Exploring the human brain [Video file]. Baltimore, MD: Author.
Note: The approximate length of this media piece is 15 minutes.
Dr. Myslinski reviews the structure and function of the human brain. Using human brains, he examines and illustrates the development of the brain and areas impacted by disorders associated with the brain.
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Laureate Education (Producer). (2012). Introduction to advanced pharmacology [Video file]. Baltimore, MD: Author.
Note: The approximate length of this media piece is 8 minutes.
In this media presentation, Dr. Terry Buttaro, associate professor of practice at Simmons School of Nursing and Health Sciences, discusses the importance of pharmacology for the advanced practice nurse.
Accessible player
To prepare for this Discussion:
Review this week’s Learning Resources.
Reflect on concepts of foundational neuroscience.
By using a combination of psychotherapy and medication therapy, psychiatric mental health nurse practitioners are positioned to provide a very unique type of care to clients with psychiatric disorders. To be successful in this role, you must have a strong theoretical foundation in pathophysiology, psychopharmacology, and neuroscience. This foundation will help you assess, diagnose, and treat clients as you relate presenting symptoms to theoretical neuronal functioning.
This week, as you begin to study psychopharmacology, you explore foundational neuroscience. You examine the agonist-to-antagonist spectrum of action of psychopharmacologic agents, compare the actions of g couple proteins to ion gated channels, and consider the role of epigenetics in pharmacologic action.
Note: In previous courses, the term “patient” was used to describe the person receiving medical care. In traditional medicine and nursing, this term is used to describe the person you do something to, and it often refers to a passive recipient of care and services. As you move into the realm of psychiatric mental health, a transition will occur. You will work with individuals who are active participants in their care, and these individuals are generally referred to as “clients” as opposed to “patients.” It is important to note that the term “client” is also favored in other mental health disciplines, such as psychiatry, psychology, and social work.
