In medicine, drugs can act either as agonist or antagonist. As an agonist, drugs bind to target receptor, changing its activity to produce a response. Agonist medications activates the full receptor in the brain while a partial agonist produces a sub-maximal response when in contact with a receptor (Berg & Clarke, 2018). On the other hand, antagonist, binds to target receptors but produces no response, hence preventing agonist from occupying the receptor. Inverse agonists lower the activity of a receptor replicating the opposite effect of an agonist (Berg & Clarke, 2018) NURS 6630 week 2 Discussion: Foundational Neuroscience.
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Actions of g Couple Proteins and Ion Gated Channels.
GPCR, found in eukaryotes, comprise of the largest known class of plasma membrane receptors. They act as principal targets for most of prescribed drugs and binds to many different types of ligands (Weir, 2019. They convert signals from extracellular ligands to signals in intracellular relay proteins, and when bonded with nucleotide guanosine triphosphate (GTP), hydrolyze it to form GDP. Ion gated channels are proteins that regulates the flow of selected ions passively across the plasma membrane. As a gated channel, they only open under specific conditions like for specific ligands (ligand-gated ion channels), or for a specific electrical potential (voltage-gated channels).
Role of Epigenetics and Pharmacologic Action
Epigenetics describes thestudy of genetic information, changes and modifications coded in gene expression. Its study has led to the understanding of many disease processes and the manufacturing of drugs to counteract such diseases (Stefanska & MacEwan, 2015). Diseases such as cancers and neurodegenerative disorders, are often associated with epigenetic alteration, can be generated by a single base mutation. With genome testing /screening, pharmacological treatments are personalized with precise disease management and prediction (Rasool et al., 2015)
Pharmacogenomics and The Impact on Mental Health Patients
Pharmacogenomics help clinicians personalized treatment to patients based on their individual’s genetic pattern and response to drugs (Butler, 2018). In the psychiatry environment, knowing the genetic make-up of patients and how they respond to specific medications can help providers predict the tolerability and metabolic impact to patients. For instance, individuals with genetic variant with CYP2C9 gene alleles with reduced enzyme activity will require a reduced dose of most medications compared to patients with a normal CYP2C9. Lithium toxicity can easily occur in patients with reduced or no enzyme activity as they metabolize medications slower leading to build of the drug in the system. The reverse can occur with patients with duplications/multiplications of the wild-type allele (Butler, 2018), metabolizes medications faster and may require a higher dose of medications.
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
Butler, M. (2018). Pharmacogenetics and psychiatric care: A review and commentary. JOURNAL OF MENTAL HEALTH AND CLINICAL PSYCHOLOGY, 2(2), 17-24. https://doi.org/10.29245/2578-2959/2018/2.1120
Rasool, M., Malik, A., Naseer, M. I., Manan, A., Ansari, S. A., Begum, I., Qazi, M. H., Pushparaj, P. N., Abuzenadah, A. M., Al-Qahtani, M. H., Kamal, M. A., & Gan, S. H. (2015). The role of epigenetics in personalized medicine: Challenges and opportunities. BMC Medical Genomics, 8(S1). https://doi.org/10.1186/1755-8794-8-s1-s5
Stefanska, B., & MacEwan, D. J. (2015). Epigenetics and pharmacology. British Journal of Pharmacology, 172(11), 2701-2704. https://doi.org/10.1111/bph.13136
Weir, C. J. (2019). Ion channels, receptors, agonists and antagonists. Anaesthesia & Intensive Care Medicine, 21(1), 62-68. https://doi.org/10.1016/j.mpaic.2019.10.022