Short photoperiods alter cannabinoid receptor expression in hypothalamic nuclei related to energy balance

This study examined the photoperiodic regulation of energy balance and cannabinoid receptor expression in the Siberian hamster (Phodopus sungorus) hypothalamus. Short day lengths, beginning at weaning, reduced food intake, body mass and fat pad masses and also decreased cannabinoid receptor immunostaining in the anterior and lateral hypothalamic nuclei of male hamsters. These data suggest a potential role for reduced cannabinoid drive in mediating short day-induced alterations in energy balance.

Research highlights► Many animals use day length to coordinate internal physiology with environmental conditions. ► Endocannabinoids are signaling molecules involved in food intake. ► Exposure to short, winter-like, day lengths reduced cannabinoid receptor expression in the hypothalamus.