Topic: Opioid Receptors – Signaling against pain always with pleasure?

This week you learned about the concept of receptors, GTP-binding  proteins and different signal transduction pathways operating in cells.  As you work on this week’s discussion board assignment, consider the  following.  
Chronic pain is one of the most common reasons adults  seek medical care. The condition has been linked to restrictions in  mobility and daily activities, anxiety and depression and often to  dependence on opioids. According to a 2016 CDC analysis of National  Health Interview Survey (NHIS) data, an estimated 20.4% (50.0 million)  of U.S. adults had chronic pain and 8.0% of U.S. adults (19.6 million)  had high-impact chronic pain. Opioid-based medications have been used by  man as an analgesic and euphoric for over 5000 years of which morphine  is the most widely known and used. Morphine and the other opioids  codeine, papaverine and thebaine are extracted from the poppy plant Papaver somniferum.  All four natural opioids bind to different opioid receptors which are  distributed throughout the central nervous system and also within  peripheral tissue of neural and non-neural origin. All opioids (natural  or synthetic) used in clinical practice today to reduce pain exert their  action at the MOP receptor. However, some have additional activities  most namely reduction in conscious level and euphoria, making them drugs  of abuse.

This week I want you to read the following scientific review article  (Pathan H. & Williams J. Basic opioid pharmacology: an update. Br.  J. Pain 6(1): 11-16 (2012) and do some research on NCBI PubMed (https://pubmed.ncbi.nlm.nih.gov/) on this week’s topic and discuss the following aspects with your class mates:

1. How many receptors have been found for opioids? What are their names?
2. How do those opioid receptors differ? Which components do they share?
3. What is known about the intracellular signaling pathways of those opioid receptors?
4. In which way might increased knowledge about the intracellular  signaling components of the opioid receptor help to develop new  generations of analgesics without addictive properties?

Be sure to include all references at the end of your initial posting  to receive full credit. These posts need to be a couple of paragraphs  and should not exceed a page (minimum of 250 words required for full  credit of original post).  You must write at least 250 words to one page and include details in your original