Medial cerebellar nucleus projects to feeding-related neurons in the ventromedial hypothalamic nucleus in rats

Abstract

The cerebellum, a hindbrain motor center, also participates in regulating nonsomatic visceral activities such as feeding control. However, the underlying neural mechanism is largely unknown. Here, we investigate whether the cerebellar medial nucleus (MN), one of the final outputs of the cerebellum, could directly project to and modulate the feeding-related neurons in the ventromedial hypothalamic nucleus (VMN), which has been traditionally implicated in feeding behavior, energy balance, and body weight regulation. The retrograde tracing results show that both GABAergic and glutamatergic projection neurons in the cerebellar MN send direct projections to the VMN. Electrical stimulation of cerebellar MN elicits an inhibitory, excitatory or biphasic response of VMN neurons. Interestingly, the VMN neurons modulated by cerebellar MN afferents not only receive phasic and tonic inputs from the gastric vagal nerves, but also are sensitive to peripheral glycemia and ghrelin signals. Moreover, a summation of inputs from the cerebellar MN and gastric vagal afferents occurs on single glycemia/ghrelin-sensitive neurons in the VMN, and the immunostaining result show that the axons from the cerebellar MN and the projections from the nucleus tractus solitarius, which conveys the gastric vagal inputs to hypothalamus, converge on single VMN glycemia/ghrelin-sensitive neurons. These results demonstrate that the somatic information forwarded by the cerebellar MN, together with the feeding signals from periphery, converge onto single VMN neurons, suggesting that a somatic-visceral integration related to feeding may occur in the VMN and the cerebellum may actively participate in the feeding regulation through the direct cerebellar MN-VMN projections.

Role of Corticotropin-Releasing Factor in Cerebellar Motor Control and Ataxia

“…The experimental procedures for retrograde tracings followed our previous report [58]. Rats (weighing 220-260 g) were anesthetized with sodium pentobarbital (40 mg/kg) and mounted on a stereotaxic frame under aseptic conditions.…”

“…The test was performed to assess motor coordination and balance of rodents [21,58]. Each rat was placed in an individual compartment of the rota-rod treadmill (Model 7750, Ugo Basile, Varese, Italy) and was required to keep walking to avoid falling off the device.…”

“…We also used a balance beam test to assess motor balance and coordination of rats [21,58]. The balance beam was a rod with length of 160 cm and diameter of 2.5 cm.…”

Fiber dissection and 3-tesla diffusion tensor tractography of the superior cerebellar peduncle in the human brain: emphasize on the cerebello-hypthalamic fibers

“…In five cases unilateral (case 1, 2, 4, 5, 6) and in two cases bilateral (case 3, 7) cerebello-hypothalamic pathways were traced and osmoregulation via the cerebello-hypothalamic projections. Li et al (2017) demonstrated that electrical stimulation of cerebellar nuclei may elicit an excitatory, inhibitory or biphasic response of ventromedial hypothalamic nucleus of the hypothalamus, which is believed to be involved in feeding behavior, energy balance, and weight control. The stimulation of the dentate nucleus and SCP of patients with tremor experienced an unpleasant sensation of fear (Nashold and Slaughter 1969).…”

Histamine Increases Neuronal Excitability and Sensitivity of the Lateral Vestibular Nucleus and Promotes Motor Behaviors via HCN Channel Coupled to H2 Receptor

“…The experimental procedures for immunostaining followed our previous reports (Zhang et al, 2011, 2013, 2016; Li et al, 2016). Rat (weighing 230–250 g) were deeply anesthetized with sodium pentobarbital and perfused transcardially with 100 ml of normal saline, followed by 450–500 ml of 4% paraformaldehyde in 0.1 M phosphate buffer.…”