Publications by authors named "T J Bartness"
We tested the hypothesis that third ventricular (3V) injections of angiotensin 1-7 (Ang 1-7) increases thermogenesis in brown adipose tissue (BAT), and whether the Mas receptor mediates this response. First, in male Siberian hamsters (n = 18), we evaluated the effect of Ang 1-7 in the interscapular BAT (IBAT) temperature and, using selective Mas receptor antagonist A-779, the role of Mas receptor in this response. Each animal received 3V injections (200 nL), with 48 h intervals: saline; Ang 1-7 (0.
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- Study Focus
- : Researchers investigated the interaction between sensory nerves in white adipose tissue (WAT) and sympathetic nervous system (SNS) pathways in brown adipose tissue (BAT), particularly how sensory feedback from WAT can influence SNS activity to various fat depots during energy challenges.
- Key Findings
- : Selectively denervating sensory nerves in inguinal WAT (IWAT) led to decreased SNS drive (norepinephrine turnover) and uncoupling protein expression in interscapular BAT (IBAT), suggesting that sensory feedback plays a crucial role in regulating SNS activity.
- Implications
- : The results suggest that IWAT sensory nerves can modify SNS communication with other fat depots,
Arcuate hypothalamus-derived agouti-related protein (AgRP) and neuropeptide Y (NPY) are critical for maintaining energy homeostasis. Fasting markedly upregulates AgRP/NPY expression and circulating ghrelin, and exogenous ghrelin treatment robustly increases acute food foraging and food intake, and chronic food hoarding behaviors in Siberian hamsters. We previously demonstrated that 3rd ventricular AgRP injection robustly stimulates acute and chronic food hoarding, largely independent of food foraging and intake.
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- The study explores how a low-carbohydrate ketogenic diet (KD) affects mice, showing that it promotes weight loss and improved insulin sensitivity, with FGF21 being a crucial mediator.
- Researchers tested mice lacking β-adrenergic receptors and found that these mice gained weight and did not increase energy expenditure while on a KD but remained insulin sensitive.
- Results indicate that while FGF21 influences liver metabolism independent of the sympathetic nervous system, the activation of energy expenditure in brown adipose tissue requires signals from the sympathetic nervous system through β-adrenergic receptors.
Article Synopsis
- * When transferred from a long-day to a short-day photoperiod, hamsters experience a natural reduction in obesity, which is reflected in the effects of MEL on white adipose tissue (WAT) lipolysis and browning.
- * The findings show that administering MEL or placing hamsters in a short-day environment increased fat breakdown and browning in their WAT, while also affecting brain regions that regulate these processes.