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

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.

Neurotransmitters and some drugs that stimulate receptors are  called agonists. Agonists stimulate receptors to their fullest signal  transduction. Drugs that act as agonists are useful in patients who lack  or are deficient in agonist neurotransmitters. In situations where the  actions of a full agonist or partial agonists are undesirable, an  antagonist is required to revert the receptor back to the state where no  agonist exists, back to neutral. Partial agonists act as they sound,  and produce a conformational change of a receptor that is halfway  between the changes of a full agonist and the baseline conformation of  that receptor. An antagonist can also reverse the effects of inverse  agonists to the receptors baseline. An inverse agonist acts to change  the conformation of a receptor to completely inactivate it and remove  the baseline constitutive activity. 

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

Both G protein coupled receptors and Ion gated channels are a  form of signal transduction cascades in the brain. They are both  triggered by neurotransmitters, and many of the psychotropic drugs used  today affect one of these two cascades. They both perform when an  extracellular first messenger passes a message to an intracellular  second messenger. However, G protein’s second messenger is a chemical,  such as adenosine monophosphate, while the ion channel second messenger  can be an ion, such as calcium. There are two classes of ion channels,  Ligand gated and voltage sensitive ion channels. The ligand gated ion  channels act similar to g protein receptors because they use the agonist  spectrum. Voltage sensitive ion channels are opened and closed based on  the voltage charge across the membrane.

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

Epigenetics determines if inherited genes are expressed or not  expressed into proteins that make up the story of any one person. The  mechanism of epigenetics turns genes on or off by modifying chromatin.  These modifications are regulated by neurotransmitters, drugs and the  environment. So drugs introduced to patients can affect a person’s  epigenetics.

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.

Understanding the way medications will affect patients based on  their genetic makeup, their current medications, the condition being  treated, what causes the imbalance, is all important when prescribing  medications. For example imipramine, a tricyclic antidepressant,  inhibits the reuptake of serotonin and norepinephrine, elevating these  neurotransmitters in the brain. It is important to understand if this is  the cause of the patients depression before prescribing this medication  because if incorrectly prescribed it could alter the patients  epigenetic mechanisms in an inverse way (Boks, et al. 2012).