SoylentNews

upstart writes in with an IRC submission:

Researchers light-up mouse brain, revealing previously hidden areas susceptible to opioids:

Although fine-tuned and evolved for complex processing, the brain and its neurotransmitters are vulnerable to hijacking by chemical substances, including opioid drugs such as oxycodone, psychostimulants such as cocaine, and alcohol. Chronic use of any of these substances enhances the activity of a molecule known as the kappa opioid receptor (KOR), which is active in the brain's reward circuitry. KOR activation produces dysphoria and an inability to feel pleasure. Its enhanced activity following chronic drug or alcohol use plays a crucial role in substance abuse.

KORs have been known to exist in certain brain regions, particularly those involved in pain processing, reward, and stress responses, but new work at the Lewis Katz School of Medicine at Temple University (LKSOM) shows that these receptors actually are distributed widely throughout the brain. The Temple researchers made this discovery after lighting up the brains of mice using a technique called CLARITY followed by three-dimensional (3D) fluorescent imaging. The study is the first to apply the imaging technique to better understand opioid receptor localization across the whole brain in 3D images.

[...] The success of the team's approach in itself is significant and could open doors to the study of other neurotransmitter receptors in the brain. KOR and other opioid receptors are types of G-protein coupled receptors (GPCRs). "No one has done a 3D study of GPCR distribution in the brain before," Dr. Liu-Chen said. "The approach we used is a very useful tool and could be applied to study many different types of GPCRs and other proteins across neural tracts."

Journal Reference:
Chongguang Chen, Alex H. Willhouse, Peng Huang, et al. Characterization of a Knock-In Mouse Line Expressing a Fusion Protein of κ Opioid Receptor Conjugated with tdTomato: 3-Dimensional Brain Imaging via CLARITY [open], eNeuro (DOI: 10.1523/ENEURO.0028-20.2020)

Original Submission