Opiate Receptors

Opiate receptors are a group of special proteins found in the brain, spinal cord, and gastrointestinal tract. These receptors connect with certain amino acids that are naturally produced by the body to initiate specific results. Opiate receptors are also affected by external opiates.

[heading style="1"]Natural Chemicals Associated with Opiate Receptors[/heading]

Opiate receptors bind with naturally occurring amino acids such as:
[list style="arrow"]

  • Dynorphins
  • Enkephalins
  • Endorphins
  • Endomorphins
[/list] These peptides each control many different functions in the brain, including:
[list style="arrow"]
  • Pain
  • Stress
  • Mood
  • Appetite
  • Sleep
  • Body Temperature
[/list] When levels of these peptides are altered due to external factors, these functions are drastically effected.

[heading style="1"]Types of Opiate Receptors[/heading]

There are three major subgroups of opiate receptors that have different effects on brain function, according to Science Daily1.

These receptor classification are:
[list style="arrow"]

  • Delta
  • Kappa
  • Mu
[/list] Each of these opiate receptor types work on different areas of the brain. Not only do opiate receptors affect functioning such as control of pain, mood, appetite, and others, they also control many of the body’s autonomous functions, those that happen involuntarily without our control. These functions include actions such as heart rate and breathing.

Opiate receptors may also play an important role in the immune system by allowing adequate functioning in immune response to invading organisms and toxins. The endocrine and reproductive systems are also affected by opiate receptors and the amino acids that bind with them.

[heading style="1"]Delta Opiate Receptors[/heading]

The delta opiate receptors, or δ-opioid receptors, have only been recently studied. It has been found that these receptors can help in the control of chronic pain and in the regulation of positive mood.

Delta opiate receptors may also play a role in substance abuse and addiction. By controlling positive mood, these receptors may affect the reward centers in the brain. In studies with mice, as reported in ScienceBlog2, those mice lacking delta opiate receptors were more likely to consume alcohol than their counterparts who had these receptors.

[heading style="1"]Kappa Opiate Receptors[/heading]

Kappa opiate receptors, or κ-opioid receptors, were studied in the past for their effects on the central nervous system in regards to pain. It has since been discovered that kappa opiate receptors more likely work on regulating mood rather than pain.

When certain chemicals affect the kappa opiate receptors, this can lead to depression and influence drug-seeking behaviors, as published in an article by Pain Research Forum3.

[heading style="1"]Mu Opiate Receptors[/heading]

Mu opiate receptors, or μ-opioid receptors, have been studies more than the others. These receptors can reduce pain and cause a sedative effect on the body. When activated, these receptors can also cause euphoria. Mice that lacked the mu opiate receptors chose not to drink alcohol, even if they had consumed it in the past3.

According to the European College of Neuropsychopharmacology in information republished in Science Daily, mu opiate receptors may actually initiate addictive behaviors when activated1. The development of chemicals that shut down these receptors may someday be helpful in reducing opiate addictions.

[heading style="1"]What Are Opiates?[/heading]

Opiates are drugs that have similar effects to opium, and are derived from the poppy plant. Synthetic, or man-made, versions of these drugs are called opioids. However, both opiates and opioids are often referred to together as simply opiates.

Opiates affect the opiate receptors in the brain, spinal cord, and gastrointestinal tract in a similar fashion as amino acids in the body. They bind with these receptors and make their way to the brain where they cause changes in the functioning of the brain and its control over systems in the body.

[heading style="1"]How Do Drugs Affect Opiate Receptors and the Body?[/heading]

As mentioned above, opiates bind with opiate receptors. This prevents naturally-occurring peptides from combining with the appropriate receptors. Over time, the body determines it doesn’t need to produce these important amino acids, as the receptors are being utilized from the drug use. The body feels it doesn’t need any more chemicals to function.

When natural dynorphins, enkephalins, endorphins, and endomorphins are no longer being produced by the body, effects can be felt when opiates have not been used recently. As the body becomes used to the level of opiate in the system, more and more is needed. This is not just to get the good feelings initially felt by drug use, but to keep from feeling bad from the uncomfortable, often painful, symptoms of withdrawal from the drug.

[heading style="1"]Withdrawal from Opiate Drugs[/heading]

Withdrawal from opiates can be an extremely unpleasant experience, depending on the drug, amount used, and length of time of use.

Symptoms of withdrawal often include:
[list style="check"]

  • Runny nose and watery eyes
  • Itching
  • Tremors
  • Nausea and vomiting
  • Muscle cramps
[/list] Withdrawing from opiate drugs may even cause seizures, spiked fever, and coma, in which case emergency personnel should be notified immediately.

Withdrawal from opiates is difficult but not impossible. It is necessary to allow the body to begin producing the naturally-occurring peptides necessary for proper functioning of many body systems.

Resources

1. European College of Neuropsychopharmacology; How Does The Opioid System Control Pain, Reward And Addictive Behavior?; Science Daily

2. Science Blog; Probing the role of the delta opioid receptor in alcohol consumption

3. Megan Talkington; Kappa Opioid Receptors: Rekindling the Flame; Pain Research Forum