Category Health/Medical

Serotonergic neurons in the dorsal raphe nucleus (DRN) and median raphe nucleus (MRN) of the brainstem differentially modulate emotional behavior. Credit: Columbia University Department of Psychiatry

More nuanced view of brainstem neurons could lead to better drugs for depression, anxiety. Low levels of serotonin in the brain are known to play a role in depression and anxiety, and it is customary to treat these disorders with medications that increase the amount of this neurotransmitter. However, a new study suggests that this approach may be too simple. It appears that neighboring serotonin-producing brainstem regions exert different and sometimes opposing effects on behavior.

“Our study breaks with the simplistic view that ‘more is good and less is bad,’ when it comes to serotonin for mo...

Highlights •Mouse V2a brainstem neurons are excitatory and project to the ventral spinal cord •Optogenetic activation of V2a neurons of the rostral medulla halts locomotion •These “V2a stop neurons” act by depressing locomotor rhythm generation •V2a stop neurons are needed for episodic locomotion

A population of ‘stop cells’ in the brainstem is essential for the ability of mice to stop their locomotion, according to a new study. Researchers report a brainstem pathway specifically dedicated to enforce locomotor arrest; its selective activation stops locomotion, while its silencing favors it. The study thus identifies a novel descending modality essential for gating the episodic nature of locomotor behavior.

Locomotion has an episodic nature: we move when we want or need and, equ...

Orexin image provided by researchers. Credit: Image courtesy of University of Tsukuba

A potent compound that promotes wakefulness and remedies the sleep disorder narcolepsy in model animals has been developed by a team of scientists. The compound works to mimic the action of a wake-promoting substance in our brain called “orexin.”.

Orexin, discovered in 1998 by Yanagisawa, is a neuropeptide that plays a central role in maintaining wakefulness. Its deficiency causes narcolepsy, in which patients experience excessive daytime sleepiness, often falling asleep uncontrollably. Patients also suffer from symptoms such as cataplexy (sudden loss of muscle tone triggered by emotion), vivid hallucinations when going into or out of sleep, and sleep paralysis...

(a) Schematic representation of HPSE biogenesis and the coexpression strategy used in this study. (b) Front view of apo-HPSE in ribbon representation. Subunits are colored yellow (8 kDa) and blue (50 kDa). Five sites of N-glycosylation are shown in green. (c) Side view of HPSE showing a binding cleft in the (β/α)8 domain in which the catalytic residues (green) reside.

Human heparanase, a sugar-degrading enzyme has received significant attention as a key target in anti-cancer treatments. Though naturally regulated in a healthy organism, heparanase is an enzyme which is produced in excessive quantities in a cancer situation...