Acute deep brain stimulation of the paraventricular nucleus of the hypothalamus increases brown adipose tissue thermogenesis in rats

FAcTs on fire: Exploring thermogenesis

Thermoregulation is a fundamental biological process that allows birds and mammals to maintain a stable internal temperature despite environmental fluctuations, a mechanism shaped by millions of years of evolution. Non-shivering thermogenesis (NST), primarily driven by brown adipose tissue (BAT), plays a central role in thermoregulation by not only helping maintain energy homeostasis but also influencing broader metabolic and physiological processes. Recent research has revealed that BAT thermogenesis is regulated by peripheral hormones and at a central level, with key hypothalamic energy-sensing pathways-such as AMP-activated protein kinase (AMPK) and endoplasmic reticulum (ER) stress-playing critical roles. Beyond its metabolic functions, BAT and NST have emerged as important contributors to tumor biology, offering novel therapeutic strategies for metabolic and oncological diseases. This review explores the intricate mechanisms underpinning NST, including UCP1-dependent thermogenesis and alternative pathways such as creatine cycling, calcium-dependent thermogenesis, and lipid cycling. Emerging evidence further highlights BAT's potential in to modulate tumor metabolism, with pharmacological and genetic approaches showing promise in reshaping the tumor microenvironment. This growing body of knowledge offers exciting prospects for targeting BAT thermogenesis in treating obesity and other metabolic diseases.

Novel hypothalamic pathways for metabolic effects of spexin

One of the main underlying etiologies of type 2 diabetes (T2DM) is insulin resistance, which is most frequently caused by obesity. Notably, the deregulation of adipokine secretion from visceral adiposity has been identified as a crucial characteristic of type 2 diabetes and obesity. Spexin is an adipokine that is released by many different tissues, including white adipocytes and the glandular stomach, and is negatively connected with the state of energy storage. This peptide acts through GALR2/3 receptors to control a wide range of metabolic processes, including inflammation, browning, lipolysis, energy expenditure, and eating behavior. Specifically, spexin can enter the hypothalamus and regulate the hypothalamic melanocortin system, which in turn balances energy expenditure and food intake. This review examines recent advances and the underlying mechanisms of spexin in obesity and T2DM. In particular, we address a range of topics from basic research to clinical findings, such as an analysis of the possible function of spexin in the hypothalamic melanocortin response, which involves reducing energy intake and increasing energy expenditure while also enhancing insulin sensitivity and glucose tolerance. Gaining more insight into the mechanisms that underlie the spexin system's control over energy metabolism and homeostasis may facilitate the development of innovative treatment approaches that focus on combating obesity and diabetes.

Radioneuromodulation of Nucleus Accumbens for Addiction: The First Animal Study

OBJECTIVE

Addiction is a serious spiral where negative events or relationships trigger a craving even when the situation is caused by the addiction in the first place. Nucleus accumbens is identified as an important hub for the neural pathways involved in the addictive behavior. Stimulation of this structure was demonstrated to be beneficial for addiction previously, but radioneuromodulation was never investigated until today. This study aimed to investigate if radioneuromodulation of the nucleus accumbens has any effect on alcohol addiction.

METHODS

An addiction model was used on 36 Long-Evans rats (18 females/18 males), via a 2-bottle intermittent access protocol, and the trial group received 100 Gy of gamma irradiation to their bilateral nucleus accumbens. Rats were followed up for an additional 15 weeks. Multiple sets of a behavioral test battery, a 4-week abstinence period, and quinine adulteration challenges were used to evaluate responses.

RESULTS

The experiment showed that the intervention reduced alcohol preference in the presence of aversive stimuli in female rats, compared with the nonirradiated control rats, because the trial group showed a 9.83-point decrease in alcohol preference rate under high-dose quinine adulteration compared with baseline, whereas the control group did not show any decrease. There were also implications of additional benefits regarding weight control in females and behavioral tests in males. No evident adverse effect was observed with the treatment.

CONCLUSIONS

This study indicates that nucleus accumbens radioneuromodulation, although not significantly affecting baseline consumption, reduces intake when an aversive stimulus is involved, implying improved self-control.

Neural circuits of long-term thermoregulatory adaptations to cold temperatures and metabolic demands

The mammalian brain controls heat generation and heat loss mechanisms that regulate body temperature and energy metabolism. Thermoeffectors include brown adipose tissue, cutaneous blood flow and skeletal muscle, and metabolic energy sources include white adipose tissue. Neural and metabolic pathways modulating the activity and functional plasticity of these mechanisms contribute not only to the optimization of function during acute challenges, such as ambient temperature changes, infection and stress, but also to longitudinal adaptations to environmental and internal changes. Exposure of humans to repeated and seasonal cold ambient conditions leads to adaptations in thermoeffectors such as habituation of cutaneous vasoconstriction and shivering. In animals that undergo hibernation and torpor, neurally regulated metabolic and thermoregulatory adaptations enable survival during periods of significant reduction in metabolic rate. In addition, changes in diet can activate accessory neural pathways that alter thermoeffector activity. This knowledge may be harnessed for therapeutic purposes, including treatments for obesity and improved means of therapeutic hypothermia.