Week 2: Neurotransmitters and Receptor Theory NURS 6630

 

 

 

           

Week 2: Neurotransmitters and Receptor Theory NURS 6630

 

 

 

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Week 2: Neurotransmitters and Receptor Theory

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 to antagonist spectrum demonstrates how pharmacological agents manage several diseases. The mode of action of agonists is through mimicking the action of neurotransmitters like adrenaline by attaching to their respective receptors to produce similar or magnified effects. Antagonists block the action of neurotransmitters leading to an opposing effect. They oppose the normal synaptic transmission (Jacobson et al., 2020). However, when it comes to determining the extent to which the agonist to antagonist spectrum affects the efficacy of psychotropic agents, it is important to look at both full and partial agonists, irreversible agonists, silent antagonists, and inverse agonists and partial antagonists. Full agonists activate the entire receptor for optimum efficacy. Partial agonists on the other hand only bind to part of the receptor leading to minimal effects as a result of partial signal transduction. Irreversible agonists bind permanently to the specific receptor to elicit the desired effect. Silent antagonists bind to the specific receptor competitively but with no intrinsic activity as the receptor is not activated. Inverse agonists bind to the specific receptor similarly to an agonist but oppose the agonist effect in addition to suppressing spontaneous signaling of the receptor if its present. Inverse agonists and partial agonists have been reported to display high selectivity among psychotropic agents hence displaying high efficacy with reduced side effects.

1. Compare and contrast the actions of g couple proteins and ion gated channels.

G protein-coupled receptors (GPCRs) are the largest family of proteins that are located on the cell surface and are responsible for recognizing extracellular substrates for signal transmission through the cell membrane (Egyed et al., 2020). On the other hand, ligand-gated ion channels (LGICs) are complex transmembrane proteins that promote the flow of ions through pore channels on the cell membrane in response to ligand binding. When activated LGICs induce intracellular alterations quickly within a span of milliseconds, in relation to the permeability and potentials of the post synaptic membrane. However, post synaptic activation of the GPCRs is normally slower and may take up to several seconds to minutes, as these receptors are responsible for regulating how ion channels open and close indirectly, to elicit the response that is desired.

1. Explain how the role of epigenetics may contribute to pharmacologic action.

Epigenetic regulation of the activity of genes has displayed great significance in maintaining the regular phenotypic activity of human cells, in addition to having a crucial role in the development and management of diseases such as neurodegenerative disorders like Alzheimer’s as well as cancer. Regulation of epigenetic mechanisms used in the development of drugs mainly targets systems like DNA methylation, chromatin modifications, and remodeling and regulation of noncoding RNA histone covalent modifications among others. For instance, several drugs like decitabine and azacytidine acting as DNA Methyltransferase (DNMT) have recently been approved by the FDA for the management of Myelodysplastic Syndrome (MDS) in oncology (Rager et al., 2019).

 

 

 

 

1. 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.

Most psychiatric patients normally tend to benefit from a combination of psychotropic agents to display synergism in alleviating the symptoms or reducing the side effects. As such, it is crucial for the PMHNP to be aware of the mode of action of each drug, to avoid adverse effects due to drug-drug interactions and manage the dosage of drugs acting on the same receptor to avoid toxicity (El-Mallakh, 2020). For instance, when managing a patient with comorbid PTSD and bipolar, mood stabilizer medications like lithium is recommended as first-line. However, SSRIs may also be prescribed such as sertraline to manage the patient’s PTSD symptoms. However, the clinician must be aware of the mode of action of each drug to regulate their dosages and avoid incidences of serotonin syndrome which can occur when a mood stabilizer is combined with an SSRI.

 

 

References

Egyed, A., Domány-Kovács, K., Koványi, B., Horti, F., Kurkó, D., Kiss, D. J., … & Keserű, G. M. (2020). Controlling receptor function from the extracellular vestibule of G-protein coupled receptors. Chemical Communications, 56(91), 14167-14170.

El-Mallakh, R. S. (2020). Posttraumatic stress disorder: From pathophysiology to pharmacology. Current Psychiatry, 19(5), 33-39. https://www.mdedge.com/psychiatry/article/221338/ptsd/posttraumatic-stress-disorder-pathophysiology-pharmacology

Jacobson, K. A., Delicado, E. G., Gachet, C., Kennedy, C., von Kügelgen, I., Li, B., … & Müller, C. E. (2020). Update of P2Y receptor pharmacology: IUPHAR Review 27. British Journal of Pharmacology, 177(11), 2413-2433. DOI: 

Rager, J. E., Suh, M., Chappell, G. A., Thompson, C. M., & Proctor, D. M. (2019). Review of transcriptomic responses to hexavalent chromium exposure in lung cells supports the role of epigenetic mediators in carcinogenesis. Toxicology letters, 305, 40-50.