Effects of silencing tuberomammillary nucleus histidine decarboxylase-lineage neurons on behavioral responses in a mouse model of motion sickness.

This study investigated the effects of manipulating tuberomammillary nucleus (TMN) histidine decarboxylase (HDC)-lineage neurons, which constitute the major source of central histaminergic neurons, on motion sickness-like behaviors in mice. Using a transgenic mouse line and a cyclic rotational stimulation paradigm, we found that rotational stimulation significantly upregulated Fos expression in the TMN. Silencing of TMN HDC-lineage neurons did not affect conditioned flavor avoidance but significantly reduced retching-like episodes following rotational stimulation. However, mice with TMN HDC-lineage neuron silencing exhibited lower baseline locomotor activity and impaired motor coordination compared to controls, which complicates interpretation of the retching-like behavior. These findings provide preliminary evidence that TMN HDC-lineage neurons may contribute to the expression of motion sickness-induced retching-like behavior, while their role in motion sickness-induced malaise-related responses and motor impairments remains to be further clarified.