We have recently shown that tanycytes signal through changes in intracellular Ca2+ and that they can respond with large Ca2+ signals to ATP and transmitters associated with wakefulness and the drive to feed. They are also glucosensitive and this response is dependent on release of ATP from tanycytes and the activation of P2Y1 receptors. Their ability to release ATP gives potential for their integration into the hypothalamic circuitry controlling energy balance and feeding, but many fundamental questions about their possible functions and roles remain unanswered.
Our current research examines tanycyte signalling still further -do they signal to neurones, what are the mechanisms of glucosensing, which other circulating signals, metabolites and transmitters are they sensitive to? What do tanycytes do in vivo? We are exploiting modern optogenetic methods to develop ways of selectively activating tanycytes to answer these questions.
Left: Movie of tanycyte response to ATP (Fura-2 ratio images). Right: Response of tanycytes to focally applied glucose from pipette.