NURS 6630 Discussion: Concepts of Foundational Neuroscience
NURS 6630 Explain The Agonist-to-Antagonist Spectrum of Action of Psychopharmacologic Agents
Explain the agonist-to-antagonist spectrum of action of psychopharmacologic agents
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 and antagonist are understood to be the main players in the human body and pharmacology and are considered as two basic drug groups, working in opposite directions where the agonist generates an action, while the antagonist opposes the action. In this case, the agonist may occur naturally or as a drug, that binds to the activated receptor, while the antagonist binds to receptors, leading to no activation, inhibiting the agonist from binding (Clark, 2018). Consequently, the agonist produces changes in the G-protein sites, activating and signaling another messenger to the highest possible extent in a cascade effect, which also works with the ligand-gated ion channels (Berg & Clarke, 2018). The antagonist in return inhibits the agonist action and stabilizes the site of the receptor in a rest state. The agonist spectrum is categorized into four types including agonist, partial agonist, antagonist, and inverse agonist. Thus, the agonist opens the channel to a full amount and regularity permitted by the site of binding, while the antagonist lying in the center of the spectrum retains the state of rest with the sporadic opening of the channel. The inverse agonist puts the ion channel in a closed and inactive state, where the antagonist holds the capability of blocking everything in the agonist spectrum, returning the ions to their state of resting in every instance. In psychopharmacologic treatments, the antagonist plays a significant role in controlling the transmission of neurons because it is the full activation of the signal transduction cascade, which may lead to undesirable impacts. Conferring to Ma, Raivio, Sabria, and Ortiz (2015), an atypical antipsychotic drug aripiprazole binds with a great affinity to the G-protein coupled receptors, which includes the Dopamine D2 receptors, though its effectiveness as a partial agonist is still contentious.
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In the second part of NURS 6630 Explain The Agonist-to-Antagonist Spectrum of Action of Psychopharmacologic Agents, Compare and contrast the actions of g couple proteins and ion gated channels.
Both the G coupling proteins and the ion gated channels’ structural patterns and the linked pathways follow the same patterns between the receptors (Clark, 2018). However, the ion gated channels bind a ligand and open a channel via the membrane, permitting special ions to go through while the G couple
protein binds the ligand, activating the protein-membrane known as G-protein, which then interacts with either the ion channel or an enzyme inside the membrane (Zhao et al., 2016). In addition, the ion gated channels response occurs within milliseconds while the response of the G couple protein occurs within seconds because of the mechanism of coupling, which adds additional complexity to stimulate a response (Stahl, 2013). This means that the G couple proteins have a slower response to signals compared to the ion gated channels.
In the third part of NURS 6630 Explain The Agonist-to-Antagonist Spectrum of Action of Psychopharmacologic Agents, Explain how the role of epigenetics may contribute to pharmacologic action.
Epigenetics is defined as the study of how our behaviors and surroundings lead to modifications affecting how our genes work (CDC, 2020). In this case, the genes are transcribed from the DNA to the RNA proteins, where the epigenetic mechanisms activate and deactivate the genes by changing the structure of the chromatin in the nucleus cells (Mason, 2018). Thus, through epigenetics, the control of the activities of the genes is significant in maintaining the cell’s normal phenotypic activities. This has been proven by extensive researches, especially in the development of ailments like cancer and neurodegenerative illnesses like Alzheimer’s (Stefanska & McEwan, 2015). However, new drug classes have been and are still developed to control the mechanism of epigenetics to respond to illnesses. For instance, Dogan et al., (2018), carried out research on integrated genetic and epigenetic prediction of coronary artery disease in a Framington heart study. The aim was to incorporate genetic and epigenetic facts to establish a classifier that will predict symptomatic CAD as a step towards showing the capability of using an incorporated method for risk models in the future as a substitute to current algorithms.
In the fourth part of NURS 6630 Explain The Agonist-to-Antagonist Spectrum of Action of Psychopharmacologic Agents, 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.
When the Psychiatric mental health nurse practitioner is prescribing medication he/she needs to understand the mechanism of action to ensure the patient is prevented or minimized from severe side effects or fatal events (Stahl, 2013). This is because the neural transmitters interact at all its subtypes of the receptor, whereas a lot of drugs tend to be more selective compared to the neurotransmitter itself for specific subtypes of the receptors (Clarks, 2018). This defines and explains the pharmacological receptor subtype, where they interact specifically. For example, when prescribing psychotropic medications the nurse needs to be more careful since a lot of drugs have been linked to prolongation of the QT interval. For instance, the use of amitriptyline is to treat depression and pain in the nerves, where the TCA prevents the channels of potassium (Stahl, 2013). As a result, this leads to hyperkalemia, which is normally linked to torsades de pointes a ventricular tachycardia, which may cause sudden cardiac death.
References
Berg, K., A., Clarke, W., P. (2018). Making Sense of Pharmacology: Inverse Agonism and Functional Selectivity, International Journal of Neuropsychopharmacology, Vol. 21, (10): 962–977. https://doi.org/10.1093/ijnp/pyy071
Clarks, C. (2018). Basic principles of pharmacology. Tulane University School of Medicine. Retrieved 2021 March, 03 from http://tmedweb.tulane.edu/pharmwiki/doku.php/basic_principles_of_pharm?do=
CDC. (2020 August, 03). What is Epigenetics? Retrieved from: https://www.cdc.gov/genomics/disease/epigenetics.htm
Dogan, M. V., Grumbach, I. M., Michaelson, J. J., & Philibert, R. A. (2018). Integrated genetic and epigenetic prediction of coronary heart disease in the Framingham Heart Study. Plos ONE, 13 (1), 1-18. doi:10.1371/journal.pone.0190549
Ma, G. F., Raivio, N., Sabria, J., & Ortiz, J. (February 19, 2015). Agonist and Antagonist Effects of Aripiprazole on D2-Like Receptors Controlling Rat Brain Dopamine Synthesis Depend on the Dopaminergic Tone. International Journal of Neuropsychopharmacology, Vol.18: 4.
Mason, L. E. (2018). Epigenetics and Drug Discovery. Retrieved 2021 February, 03 from: Technology Networks: https://www.technologynetworks.com/drug-discovery/articles/epigenetics-and-drug-discovery-306821
Stefanska, B., & McEwan, D. J. (2015). Epigenetics and pharmacology. British journal of pharmacology, Vol. 172 (11): 2701-4. doi: 10.1111/bph.13136
Stahl, S. M. (2013). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications (4th ed.). New York, NY: Cambridge University Press
Zhao, J., Deng, Y., Jiang, Z., Oing, H. (2016). G Protein-Coupled Receptors (GPCRs) in Alzheimer’s Disease; A Focus om BACE1 Related GPCRs. Frontier in Aging Neuroscience. https://doi.org/10.3389/fnagi.2016.00058
Foundational Neuroscience
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.
An inverse agonist binds to the receptor and prevents the occurrence of the normal activity and exerts the occurrence of an opposite pharmacological action. An agonist binds to a receptor resulting in the activation of the receptor and signal transduction leading to a biological response. On the other hand, an antagonist binds to a receptor and blocks it from binding in any agonist, resulting in no biological response. A partial agonist binds and results in the activation of a receptor but only with partial efficacy that is relative to the endogenous and full agonist (Berg & Clarke, 2018).
Compare and contrast the actions of g couple proteins and ion gated channels.
Both the g-protein and ion gated channels are triggered by the neurotransmitters. They are, however, distinct in the sense the g-couple proteins are involved in the transmission of signals to different transductions within a cell, whereas the ion gated channels trigger the movement of certain types of ions through receptors by selectively opening and closing. They are similar in some way- both allow both the transmission of signals and ions internally. The G-couple originates from the plasma (Stahl, 2018).
Explain how the role of epigenetics may contribute to pharmacologic action.
Epigenetics comprise heritable genetic modifications that alter gene function and expression without changes in DNA sequence. Epigenetics explains the capability of gene expression regulation without modifying the genetic sequence. Epigenetic mechanisms occur due to alterations in either the molecules or characteristics that, in turn, affect the gene expression without changing sequences of DNA, DNA methylation, histone modification, and non-coding RNAs(Waghmare et al., 2020).
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.
It is clear that a lot remains to be discovered in terms of the effect of epigenetics in neuroscience. New evidence implicates the dysregulation of epigenetic mechanisms in neurodegenerative disorders and diseases. This necessitates openness in terms of thinking about the effects of epigenetics when administering medications (Waghmare et al., 2020).
References
Berg, K. A., & Clarke, W. P. (2018). Making Sense of Pharmacology: Inverse Agonism and Functional Selectivity. International Journal of Neuropsychopharmacology, 21(10), 962. https://doi.org/10.1093/IJNP/PYY071
Stahl, S. M. (2018). Stahl’s Essential Psychopharmacology: Neuroscientific basis and practical applications (4th ed.). New York, NY: Cambridge University Press
Waghmare, S. S., Bhusnure, O. G., Mali, M. R., & Mule, S. T. (2020). Epigenetics: Pharmacology and Modification Mechanisms Involved in Cardiac, Hepatic and Renal Disease. Journal of Drug Delivery and Therapeutics, 10(4), 260–266. https://doi.org/10.22270/JDDT.V10I4.4148