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18 hours ago

Casey Hoffman 

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 The agonist-to-antagonist spectrum of action of psychopharmacologic agents:

 The agonist-to-antagonist spectrum of action involves ligands, which act as full agonists, antagonists, partial agonists, and inverse agonists. By changing the conformation of receptors, full agonists open the ion channel to the higest amount of frequency allowed by the specific binding site (Stahl, 2013). In contrast, antagonists reverse the action of agonists by stabilizing the receptor in the resting state (Stahl, 2013). Partial agonists create an alteration in the conformation of the receptor, which then cause the ion channel to open wider and more often than it does in the resting state (Stahl, 2013). Partial agonists however, open less frequently when they are in the presence of a full agonist. Inverse agonists are the complete opposite of agonists in that they produce conformation change in the receptors by closing it and stabilizing it in an inactive form (Stahl, 2013). This process produces a functional decrease in the flow of the ions and signal transduction compared to the resting state (Stahl, 2013). Inverse agonists are called stabilizers because of the stabilization that occurs in an inactive form. 

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

The majority of medications that are used in psychopharmacology, specifically target ion channels. When specific molecular sites are targeted, alterations occur in the synaptic neurotransmission that is directly linked to the therapeutic actions of numerous psychotropic medications (Stahl, 2013). Ion channels consist of 2 major classes, ligand-gated ion channels, and voltage-sensitive ion channels (Stahl, 2013). Ligand-gated ion channels are made up of both channels and receptors. Neurotransmitters are responsible for opening the ligand-gated ion channels.  Voltage-sensitive ion channels open by controlling the charge across the membrane in which they are located (Stahl, 2013). G-protein-linked and ion-channel linked are triggered by neurotransmitters. Ion-channels are activated by the 1st messenger neurotransmitter, which then activates the 2nd messenger, calcium (Stahl, 2013). Calcium then activates the 3rd messenger, kinase calcium/calmodulin-dependent protein kinase (CaMK). The second messenger also influences gene expression through the 4th messenger, CREB, which binds with phosphate in the post-synaptic cell nucleus.  G-proteins are activated by the 1st messenger neurotransmitter. which activates genes in the cell nucleus by phosphorylating 2nd messenger protein cAMP (cyclic adenosine monophosphate) and 3rd messenger protein kinase A (Stahl, 2013). The 4th messenger is then activated by this process. The 4th messenger cAMP response element-binding protein, which the binds with phosphate to cause gene expression to turn on in the post-synaptic cell nucleus.  

Explain the role of epigenetics in pharmacologic action.

According to the authors Rasool, Malik, Naseer, & Manan (2015), epigentics is the study of changes in organisms caused by a modification of gene expression rather than alteration of the genetic code itself. Epigentic alterations occur when there are modifications in gene expression that are independent of the DNA sequence of a gene (Rasool, Malik, Naseer, & Manan, 2015). Epigentic alterations can be extremely influential regarding health and disease states (Rasool, Malik, Naseer, & Manan, 2015). These alterations can include changes to methylation, acetylation, phosphorylation, and ubiquitylation of DNA and proteins. In order to appropriately treat specific disease states, more broad-acting medications are being developed, which target multiple proteins (Stefanska & MacEwan, 2015). Broad-acting medications are essential in psychopharmacology because many diseases are made up of more than one mutation, which make drug-receptor medications not as effective. 

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.

It is essential for psychiatric nurse practitioners to have a thorough understanding of the mechanism of action for the medication they are prescribing. When prescribing Zoloft for a client who is suffering from Major Depressive Disorder (MDD), the PMHNP should be aware that this medication is a serotonin reuptake inhibitor. By inhibiting the reuptake of serotonin, the imbalance of the serotonin levels is corrected. Zoloft inhibits the CNS neuronal uptake of 5HT (serotonin). 

Rasool, M., Malik, A., Naseer, M. I., & Manan, A. (2015). The role of epigenetics in personalized

medicine: challenges and opportunities. BMC medical genomics, 8(1). https://doi.org/10.1186/

1755-8794-8-S1-S5

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

Stefanska, B., & MacEwan, D. J. (2015). Epigenetics and pharmacology. British journal of

pharmacology, 172(11), 2701-2704.