RESUMEN
The regulation of food intake and energy balance relies on the dynamic integration of exteroceptive and interoceptive signals monitoring nutritional, metabolic, cognitive, and emotional states. The paraventricular thalamus (PVT) is a central hub that, by integrating sensory, metabolic, and emotional states, may contribute to the regulation of feeding and homeostatic/allostatic processes. However, the underlying PVT circuits still remain elusive. Here, we aimed at unravelling the role of catecholaminergic (CA) inputs to the PVT in scaling feeding and metabolic efficiency. First, using region-specific retrograde disruption of CA projections, we show that PVT CA inputs mainly arise from the hindbrain, notably the locus coeruleus (LC) and the nucleus tractus solitarius. Second, taking advantage of integrative calorimetric measurements of metabolic efficiency, we reveal that CA inputs to the PVT scale adaptive feeding and metabolic responses in environmental, behavioural, physiological, and metabolic stress-like contexts. Third, we show that hindbrainTH âPVT inputs contribute to modulating the activity of PVT as well as lateral and dorsomedial hypothalamic neurons. In conclusion, the present study, by assessing the key role of CA inputs to the PVT in scaling homeostatic/allostatic regulations of feeding patterns, reveals the integrative and converging hindbrainTH âPVT paths that contribute to whole-body metabolic adaptations in stress-like contexts. KEY POINTS: The paraventricular thalamus (PVT) is known to receive projections from the hindbrain. Here, we confirm and further extend current knowledge on the existence of hindbrainTH âPVT catecholaminergic inputs, notably from the locus coeruleus and the nucleus tractus solitarius, with the nucleus tractus solitarius representing the main source. Disruption of hindbrainTH âPVT inputs contributes to the modulation of PVT neuron activity. HindbrainTH âPVT inputs scale feeding strategies in environmental, behavioural, physiological, and metabolic stress-like contexts. HindbrainTH âPVT inputs participate in regulating metabolic efficiency and nutrient partitioning in stress-like contexts. HindbrainTH âPVT inputs, directly and/or indirectly, contribute to modulating the downstream activity of lateral and dorsomedial hypothalamic neurons.
Asunto(s)
Núcleo Solitario , Tálamo , Conducta Alimentaria/fisiología , Hipotálamo , Neuronas/fisiología , Núcleo Hipotalámico Paraventricular , Tálamo/fisiologíaRESUMEN
Neurons within the arcuate nucleus control energy balance and represent the functional substrates through which FGF1 deploys its anti-diabetic action. Alonge et al. (2020) now report that the integrity of arcuate perineuronal nets, an extracellular matrix component that enmeshes GABAergic neurons, is reversibly altered in diabetic rats and a key component for FGF1-mediated diabetic remission. These novel insights unravel how perineuronal nets dynamically contribute to the central control of glycemia.