Hypothalamic tanycytes
Supported by the MRC and BBSRC
Hypothalamic tanycytes are cells that line the walls of the 3rd ventricle. Their cell bodies contact the cerebrospinal fluid and give rise to an inwardly directed process. The more dorsally located tanycytes project to areas of the brain involved in the control of feeding and energy balance (the arcuate nucleus and ventromedial hypothalamic nucleus). Although their functions are poorly understood, they have some similarities to glial cells. Recent evidence shows that they express key molecules involved in purinergic signaling and at least some tanycytes may act as adult multipotent stem cells.
The brain plays a vital role in the regulation of food intake, appetite and ultimately bodyweight. Neurons in the hypothalamic arcuate nucleus the ventromedial hypothalamic nucleus and the lateral hypothalamus are sensitive to a number of circulating signals such as leptin, grehlin, insulin and glucose. These neurons are part of a network that integrates this information to regulate feeding and appetite. The proximity of tanycytes to these nuclei and the projection of their processes into them has led to speculation that tanycytes might be a part of the network that controls energy expenditure and food intake.
Banner illustration: Ca2+ signals in tanycytes during focal application of glucose. Montage of 4 images, 16s apart; blue ovals indicate ROIs over responsive tanycytes; 3v, 3rd ventricle.