The effects of unilateral lesion of the tuberomammillary nucleus E2 sub-region on nocturnal feeding and related behaviors in mice.

Aims: Bilateral lesions of the mesencephalic trigeminal sensory nucleus (Me5), which receives histaminergic neurons from the tuberomammillary nucleus (TMN), alter nocturnal feeding and related behaviors in mice, concomitant with a decrease in orexin mRNA level in the perifornical area (PFA) during the dark phase. Therefore, we investigated the neuronal input to the TMN from the Me5, as well as the effects of TMN lesions on the circadian profiles of feeding and related behaviors.

Main Methods: We examined the presence of neurons projecting from the Me5 to the TMN by direct injection of a retrograde tracer, Fluorogold, into the TMN E2 sub-region (TMN-E2).