BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: receptors

Obesity Related to the Brain

Lauri Nummenmaa has done research the connects obesity to the brain.  This research shows that people struggling with obesity have a lower amount of μ-opioid receptors available for binding in the brain.  (To learn more about μ-opioid receptors click here.)  Due to evolution, our brains are still “wired” to search for food and nutrients.  Since eating gives off a sensation in the brain, related to the opioid receptors, people with fewer receptors that are able to bind will therefore eat more to make up for the loss in sensation.  This reaction is the same as a reaction to an addiction would be, causing more neurotransmitters to be secreted.  The next step that scientists are taking is to discover whether being obese causes a lack in opioid receptors, or if a lack in opioid receptors, caused by another source, is what causes obesity.  One test that scientists did was testing μ-opioid receptors in people that had bariatric surgery.  Bariatric surgery causes more receptors to work again, shown by the fact that scientists could not distinguish between the μ-opioid receptors or healthy people and the μ-opioid receptors of people who had the surgery.

Some body fat, however, is helpful to the brain.  This article describes that “fat tissue in the bodies of mice releases an extracellular form of nicotinamide phosphoribosyltransferase (eNAMPT), an enzyme that travels to the hypothalamus, and gives animals energy during fasting.”  (To learn more about eNAMPT click here.)

This photo shows how a neurotransmitter is sent from neuron to neuron generally.

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(Link to Photo Page and Link to Licensing Page)

Oh the Irony: Spice Receptors Responsible for Cold Sensations

 

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For some people, experiencing cold temperatures translates to an extreme and painful sensation, rather than just “feeling chilly”. This type of pain can even occur at milder temperatures of 68°F and below. When studying the body’s mechanism responsible for connecting cold and pain, researchers at Lund University in Sweden recently discovered that the receptor involved here is the same receptor which reacts to substances in garlic and mustard.

There has been lots of research regarding the connections between pain and irritant substances in mustard, garlic and chili. When consumed in mass amounts, these spices can cause burning sensations, rashes, swelling, and when exposed to the eyes, crying. The substances in the spices affect nerves involved in the pain system and are activated by inflammation. In the case of the garlic and mustard receptor, the Lund research team noted the way powerful substances in the garlic and mustard irritated the nerve cells 10 years ago. These receptors are found throughout the body, in places such as the skin, bladder and gut. TRPA1 is the ion channel, associated with sensory processes, activated by garlic extracts and mustard oil.  with  Now, the scientists have extended their research to prove that this garlic and mustard receptor also responds to cold.

By extracting the human receptor protein and inserting into an artificial cell membrane, the Lund scientists were able to see its reactions to cold. The scientists executed their experiment hoping get a better understanding of the body’s temperature senses and help for cold allodynia sufferers. People with chronic pain or diseases often experience problems affecting the nervous system. For instance, cancer patients undergoing chemotherapy treatments can experience the side-effect of becoming over-sensitized to cold. The pain experienced by patients and the reaction for the garlic and mustard receptor both begin at relatively mild temperatures.

Drug companies are attempting to address this issue by developing drugs which will block the receptors, hopefully reducing the inflammation side effects and general pain. The Lund team believes this application will also relieve the pain caused by cold. The garlic and mustard receptor reacts to chemical substances acting as airway irritants. To address this issue, a new plausible solution of a drug which helps those affected by perfume, smoke and other irritants is believed to also help people suffering from over-sensitizing cold in their airways.

The connection of the garlic and mustard receptor to cold helps us further understand the precision and specificity of the our body’s abilities in temperature sensing. Substances in spices (notoriously hot and well, spicy) can react in ways to bring about extreme pain from over-sensitivity to cold. It’s wild that the body’s sensory neurons can share receptors and cause similar reactions to very different triggers (spice substances and the cold). It’s pretty amazing that medication is being developed to block the receptors for both substances, lessening the pain and inflammation for these seemingly polar issues. It turns out that science, involved in even the tiniest receptor, really does connect everything.

 

Sources:

http://www.sciencedaily.com/releases/2014/11/141113085154.htm

http://www.ncbi.nlm.nih.gov/books/NBK5237/

http://www.achenet.org/resources/allodynia_when_touch_hurts_but_shouldnt/

 

 

Photograph :

Images by John ‘K’

Wild Mustard Flowers

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