Daylight hours can affect opioid receptor levels in brown fat

When the seasons darken and become colder, the brown fat of the animals begins to grow
.
This tissue produces heat efficiently and quickly and regulates appetite
.
Brown fat is also found in the human body
.

In a new study conducted at the PET Center in Turku, Finland, researchers observed that shorter hours of sunshine affect signaling
of opioid receptors in brown fats in animals.
When light decreases, opioid receptor levels increase
.
Observations are made
in an artificial environment that simulates seasonal daylight changes.

"In the study, we observed that the number of muu-opioid receptors in brown fat depends on how long rats are exposed to sunlight
.
This complements our previous findings that day length regulates opioid receptor levels in the emotional circuits of the human and rat brains," said
Sun Lihua, a senior researcher at the University of Turku's PET Center in Turku.

He noted that brown fat and the brain's opioid receptor activity are two different phenomena
.
However, they share a common goal of helping mammals, people or animals adapt physiologically and emotionally to seasonal changes
.

"Opioid receptor levels and brown fats in the brain may be interrelated, such as enhancing each other's activity, but more research is needed to confirm this," Sun stressed
.

The new conquest of opioid receptor research

Professor Anne Roivainen, from the PET Centre in Turku, said this was the first time positron emission tomography (PET) imaging had been used to assess mu-opioid receptor levels in
the peripheral region.

"This finding underscores the seasonality
of mu-opioid receptors that affect brown fat activity.
Future studies should further investigate whether mu-opioid receptors in brown fat are directly related to tissue energy expenditure," Roivainen said
.

Opioid receptors are part of the cell through which opioid hormones can affect cells
.
An example of this hormone is endorphins, which promote pleasure and reduce pain
in the body.

Thus, the function of opioid receptors in the brain plays a central role
in both pain and emotion and emotion.
Receptor dysfunction has been linked
to mental disorders such as depression, anxiety, and eating disorders.
Opioid receptor levels are also important
for seasonal mood changes, such as seasonal mood disorders.
Symptoms include winter blue and overeating
.

According to Roivainen and Sun, more scientific evidence is needed for more scientific evidence
, according to Roivainen and Sun whether seasonal changes in muu-opioid receptor levels in the brain and brown fat are the basis for seasonal affective changes.

Journal Reference:

1. Lihua Sun, Richard Aarnio, Erika Atencio Herre, Salli Kä rnä , Senthil Palani, Helena Virtanen, Heidi Liljenbä ck, Jenni Virta, Aake Honkaniemi, Vesa Oikonen, Chunlei Han, Sanna Laurila, Marco Bucci, Semi Helin, Emrah Yatkin, Lauri Nummenmaa, Pirjo Nuutila, Jing Tang, Anne Roivainen.
   [11C]carfentanil PET imaging for studying the peripheral opioid system in vivo: effect of photoperiod on mu-opioid receptor availability in brown adipose tissue.
   European Journal of Nuclear Medicine and Molecular Imaging, 2022; DOI: 10.
   1007/s00259-022-05969-5