NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay

NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay

Week 1 Discussion: Initial Post

Foundational Neuroscience

Agonist to antagonist spectrum of action of psychopharmacologic agents

Agonist of psychopharmacologic agents binds to neurotransmitter and caused an activation of receptors; whereas, antagonist agents then binds to those receptors that are activated by agonists, thus preventing them from being in an inactivated state; thus, causing them to be in the state that is desirable (Stahl, 2013). One such example can be seen from the neurotransmitter receptors dopamine, serotonin and norepinephrine.


G-protein is a protein that binds energy molecules, they are the biggest and most versatile of proteins, their job is to activate intracellular action by signaling pathways and modulate activities of ion channel (Gohar, 2018). Ion channels are transmembrane proteins that regulates the movement of ions across cell membranes and then divide them into groups according to their specificity, some of which includes sodium channels, potassium channels and calcium channels (Gohar, 2018). NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay

Ion channel receptors are mostly multimeric proteins that are found in the plasma membrane, they form pathways from one membrane to the next; they are able to open and close chemical and mechanical signals; when these ion channels are in an open site, then they move in and out of the cell, they each have a specific allowing only one ion to pass through (Suitable by Nature, n.d).

G-protein receptors are receptors that interact with neurotransmitters as well as psychotropic medication.  G-protein and ion channel are triggered by neurotransmitters; both starts with a different messenger that binds to a specific receptor that causes activation of different downstream chemical messenger; both G-protein and Ion channels signals transduction; G-protein uses protein kinase, its job is to activate or inactive ion channels or open and close the sequence to regulate ion concentration (Stahl, 2013).


Epigenetics is described as the formation of genetics that above information coded exclusively by one’s genetic code (Stefanska & MacEwan, 2015).  Epigenetics is a system that determine if there are any gene that is made into RNA and protein specific to that gene, if is silenced; it turns genes on and off by the modification of chromatin structure that is in the cell nucleus (Stahl, 2013).  There are circumstances in which epigenetics pattern of gene activation may change from stabilization  of a silenced gene making it active or an active one, silenced based on what happens to a neuron; where pharmacologic agent can be a factor; it may cause a favorable or unfavorable response; a favorable response can be the good/therapeutic epigenetic effect where one is triggered to learn something or unfavorable effect where one is triggered to e addicted to drugs or develops conditions like anxiety disorder (Stahl, 2013). NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay

How we respond to pharmacological agents can be affected by epigenetics; drugs that are epigenetic may help in drug therapies as well as operations and management of pain (Stefanska & MacEwan, 2015).

An example is how those with a diagnosis of schizophrenia is treated; the pharmacological agent that is used to treat it, acts by reducing dopamine levels in the brain; the antagonist of dopamine works by binding the receptors causing a deactivation (Stahl, 2013).


Gohar, O. (2018). Ion channel modulation by g-protein coupled receptors. Alomone Labs. Retrieved from

Stefanska, B., & MacEwan, D. J. (2015). Epigenetics and pharmacology. British Journal of Pharmacology172(11), 2701–2704.

Stahl, S. M. (2013). Stahl’s essential psychopharmacology: Neuroscientific basis and practical applications (4th ed.). New York, NY: Cambridge University Press

Suitable by Nature. (n.d.). Ion Channel | Learn science at suitable. Retrieved from


agonist is a drug that activates certain receptors in the brain. An antagonist drug blocks opioids by attaching to the opioid receptors without activating them. Antagonists cause no opioid effect and block full agonist opioids (Stahl, 2013). A GTP-binding protein that relays signals from a plasma membrane signal receptor, known as a G protein-coupled receptor, to other signal transduction proteins inside the cell( Stahl,2013). A protein pore in cellular membranes that opens or closes in response to a signaling chemical (its ligand), allowing or blocking the flow of specific ions. Ion channel receptors are usually multimeric proteins located in the plasma membrane (Stahl, 2015). Each of these proteins arranges itself so that it forms a passageway or pore extending from one side of the membrane to the other. These passageways, or ion channels, have the ability to open and close in response to chemical or mechanical signals. When an ion channel is open, ions move into or out of the cell in single-file fashion. Individual ion channels are specific to particular ions, meaning that they usually allow only a single type of ion to pass through them ( Stahl, 2015).                                                                                                                        Epigenetics is the study of heritable changes in gene expression (active versus inactive genes) that do not involve changes to the underlying DNA sequence — a change in phenotype without a change in genotype — which in turn affects how cells read the genes(  Deans, C. & Maggert ,2015 ). Epigenetic change is a regular and natural occurrence but can also be influenced by several factors including age, the environment/lifestyle, and disease state. Epigenetic modifications can manifest as commonly as the manner in which cells terminally differentiate to end up as skin cells, liver cells, brain cells, etc. Or, epigenetic change can have more damaging effects that can result in diseases like cancer. At least three systems including DNA methylation, histone modification and non-coding RNA (ncRNA)-associated gene silencing are currently considered to initiate and sustain epigenetic change ( Deans, C. & Maggert , 2015 ). NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay

Psychotropic drugs are valuable resources in treating many mental health illnesses, but inappropriate prescribing can cause serious harm or possible death. The high numbers of inappropriate prescribing is associated with increased morbidity, mortality and decrease in quality of life ( Curkovic, Dodig-Curkovic , Eric, Kralik & Pivac, 2016  ). It is estimated that 30% of elderly people’s admissions in hospitals is due to problems related to drugs or to toxic effects of drugs ( Curkovic, Dodig-Curkovic , Eric, Kralik & Pivac, 2016 ). The elderly population is at great risk of adverse drug effects. The elderly experience altered pharmacokinetics and pharmacodynamics, which result in prolonged and increased effects of many drugs. The altered pharmacodynamics of the aging brain leads to a higher sensitivity to central nervous system acting agents ( Curkovic, Dodig-Curkovic , Eric, Kralik & Pivac, 2016        ).

Antidepressants, anxiolytics and antipsychotics are the most common potentially inappropriate psychotropics. Tricyclic antidepressants can causes dementia, cardiac conductive abnormalities, chronic constipation, and other adverse reactions (Sharma, Loh,., Nightingale, Mohile, & Holmes,2016 ). Tricyclic antidepressants should be avoided due to the anticholinergic, sedating and orthostatic hypotension   Selective serotonin reuptake inhibitors (SSRIs) should be used with caution, as they may exacerbate or cause syndrome of inappropriate antidiuretic hormone secretion or hyponatremia. Also, some drug-interactions involving antidepressants offer risks, i.e. tricyclic antidepressants and SSRIs, shows increased risk of falls (Sharma, Loh,., Nightingale, Mohile, & Holmes,2016 ). NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay



NURS 6630

Foundational Neuroscience

Explain the agonist-to-antagonist spectrum of action of psychopharmacologic agents

Psychopharmacologic agents induce changes in people’s thinking, mood, and behavior. They act through interaction with target receptors or sites in the nervous system to induce changes in patient’s psychological or physiological functions. According to Stahl (2013), most psychopharmacological drugs target ion channels or enzymes where they lead to production of biological responses among patients. This process is achieved through binding of pharmacological agents to receptors.

In pharmacology, ligands are molecules which bind to receptors. Once they bind to receptors, ligands can lead to production of biological responses or block the production of biological responses. Agonists are ligands responsible for activating receptors to produce biological response. On the other hand, antagonists are ligands which block agonist mediated responses. While agonists execute their task by activating receptors to produce biological responses, the antagonists block receptor activation, thus making it impossible to produce any biological responses.

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

G couple proteins transmit signals from stimuli outside the interior of the cell to its interior. They act as molecular switches inside the cell. Action of G couple proteins is controlled by factors that regulate their ability to bind and hydrolyze guanosine triphosphate (GTP) to guanosine diphosphate (GDP) (Lodish et al, 2000). G couple proteins are turned off when bound to GDP and are turned on when bound on GTP. According to Lodish et al (2000), different mammalian cell-surface receptors have a trimeric signal transducing G protein. Ligands which bind to these receptors activate their relevant G protein, which in turn activates the effector enzyme to produce intracellular second massager (Lodish et al, 2000). It is worth noting that all G protein coupled receptors have 7-membrane spanning areas within their N-terminal segment. NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay. On the other hand, ion gated channels are transmembrane proteins of excited cells which only allow ions to pass under specific circumstances (Stahl, 2013). Gated ion channels may be either sodium channels of neurons or voltage gated channels like the acetylcholine

Explain the role of epigenetics in pharmacologic action

Epigenetics are changes occurring in human beings as a result of modifications of gene expression rather than alteration of the real genetic code. According to Stahl (2013), epigenetics affects ways in which cells read genes and produce proteins. Through epigenetics, some genes can be expressed over time or become dormant. Epigenetics makes each person unique and is reversible. It is worth noting that there are many different combinations of genes that can be turned on or off through pharmacologic action thus impacting the health outcome of an individual. For example, if genetic combinations leading to bad states in human health can be eliminated while only maintaining the gene’s states that foster good health, then some health conditions can be successfully eliminated.

According to Lundstrom (2015), epigenetic mechanisms which focus on miRNAs are important as diagnostic biomarkers. The reversible nature of epigenetic modifications makes the inhibition of DNA methylation possible against psychiatric diseases such as bipolar disorders and schizophrenia as well as some forms of cancers and other terminal illnesses. It is important for nurse practitioners to understand how medications impact on the patient’s gene expression among psychiatric patients. Some medications may suppress certain types of gene expression responsible for aggression among mentally ill patients and make them dormant while others may enhance gene expression and result to exacerbation of patient’s symptoms. NURS 6630 Week 1 discussion – Agonist to antagonist spectrum of action of psychopharmacologic agents Sample essay.



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