Fig. 5.

Transient release of ATP in the eye field of the developing embryo. ATP and Null (no enzyme control) biosensors were placed in the anterior part of the developing neural plate in the eye fields, and a second ATP biosensor at a more posterior location (inset). Recordings were from embryonic stage 11 (before expression of the eye-field transcription factor genes) to 12.5. Midway through, a transient period of ATP release was observed in the eye field (main traces and inset). This ATP may represent the trigger (after conversion to ADP) for expression of the eye-field transcription factor genes. Note that ATP release does not occur at this time in the posterior location, although at later times, there is a clearly substantial ATP release in this location that may be involved in the control of the development of the future nervous system. Reproduced with permission from [64]