Explain how this information may impact the way you prescribe medications to clients. Include a specific example of a situation or case with a client in which the psychiatric mental health nurse practitioner must be aware of the medication’s action. NURS – 6630 Discussion: Foundational Neuroscience

Agonists are drugs with both affinity (they bind to the target receptor) and intrinsic efficacy (they change receptor activity to produce a response (NCBI 2018). Antagonists have affinity but zero intrinsic efficacy and therefore they bind to the target receptor but do not produce a response. By occupying a fraction of the receptor population an antagonist reduces the probability of occupancy by an agonist. The presence of an antagonist will reduce receptor occupancy by an agonist with a corresponding reduction in response. By increasing the concentration of the agonist, the probability of receptor occupancy by the agonist increases, and thus the inhibitory/blocking effect of the antagonist can be surmounted (NCBI 2018). As intrinsic efficacy differs with drug structure, agonists can have different intrinsic efficacies and consequently be characterized as full or partial agonists. A full agonist typically produces the maximal response a system is capable of, whereas a partial agonist produces a submaximal response (NCBI 2018).

G proteins are a family of proteins that act as molecular switches inside cells and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. G-protein-coupled receptors (GPCRs) mediate most of our physiological responses to hormones, neurotransmitters, and environmental stimulants, and so have great potential as therapeutic targets for a broad spectrum of diseases (NCBI 2009). GPCRs are the largest family of membrane proteins and mediate most cellular responses to hormones and neurotransmitters, as well as being responsible for vision, olfaction, and taste (NCBI 2009). G protein-coupled receptors (GPCRs) are involved in the control of every aspect of our behavior and physiology (Hamm 2001). More than half of all drugs target GPCRs and either activate or inactivate them. GPCRs have a common body plan with seven transmembrane helices (Hamm 2001).

Ligand-gated ion channels (LGICs) are integral membrane proteins that contain a pore which allows the regulated flow of selected ions across the plasma membrane (Alexander et al,2017). Ligand-gated ion channels bind neurotransmitters and open in response to ligand binding. These channels control synaptic transmission between two neurons or between a neuron and a muscle. Ion channel function is modulated by interactions with other proteins (Alexander et al,2017).

Epigenetics is a mechanism of gene control that can promote or repress the expression of genes without altering the genetic coding of an organism (NCBI 2011). It represents a system by which the gene expression of an individual can be altered without altering their genome’s sequence. Unlike genetic changes, epigenetic changes are reversible and do not change the DNA sequence, but it can change how the body reads a DNA sequence (NCBI 2011). The disease may be caused by direct changes in epigenetic marks, such as DNA methylation found to affect imprinted gene regulation. Studies have found that exposure to risk factors such as toxins, stress, and unhealthy diets are associated with epigenetic changes which are associated with mental health problems. Epigenetic drugs belong to a category of drugs used for the treatment of specific cancers. These drugs fall into two groups DNA methylation inhibitors and histone deacetylase inhibitors (NCBI 2011). A nurse practitioner should be careful when prescribing psychiatric medication for a patient who is diagnosed with cancer or has a strong family history of cancer.

References

Alexander, S. P., Peters, J. A., Kelly, E., Marrion, N. V., Faccenda, E., Harding, S. D., Pawson, A. J., Sharman, J. L., Southan, C., & Davies, J. A. (2017). THE CONCISE GUIDE TO PHARMACOLOGY 2017/18: Ligand-gated ion channels. British Journal of Pharmacology, 174 Suppl 1, S130–S159. https://doi.org/10.1111/bph.13879