Hypothalamus

Until now, the BDNF–TrkB signalling pathway was thought to be exclusively regulated by neurons. Ameroso et al. show that astrocytic TrkB.T1 is a critical substrate of BDNF in the regulation of energy balance and that its defective signalling in hypothalamic circuits leads to obesity.

The raphe nucleus contains specific populations of serotonergic neurons that express either orexin type 1 or type 2 receptors that directionally regulate plasma glucose and peripheral energy metabolism.

Over-nutrition is a major driver of obesity, but the mechanisms that promote and perpetuate it remain poorly understood. A recent study explores a role for umami taste in driving leptin resistance, hyperphagia and hypothalamic inflammation via overproduction of uric acid.

After establishing a novel operant conditioning paradigm that enables mice to report their interoceptive hunger state (fasted or sated), the authors investigated the hypothalamic neural circuitry that underpins these internal states using optogenetics and chemogenetics.