Light is an energy source and a visual information source in life activities, and is also used as input information for life activities by adjusting the "body clock".Although the role of light and the mechanism of transmitting light stimuli are being elucidated, there are few research reports on echinoderms, which are sister groups to chordates including humans, and how the mechanism of light response appears in the process of evolution. It was difficult to truly argue whether it was diversified.

　The research group observed larvae exposed to light at about half the intensity of sunlight under a microscope to confirm the presence or absence of a descriptive photoresponse pathway in the echinoderm Bafununi.As a result, the pylorus of the larva opened about 2 minutes after the light irradiation.The pyloric opening of many animals is controlled by the stimulation of food in the stomach, but this light-stimulated pyloric opening occurs before food intake, and one of the functions of light is the control of the digestive tract. It is said to show that there is.

　In addition, the pathway of light conduction was also found from the experiments using sea urchin larvae.First, the sea urchin's brain released the neurotransmitter serotonin, the stimulus was transmitted to cells near the pylorus, and nitric oxide was released to open the mouth.

　This time, it was found that the communication from the brain to the intestine is responsible for the transmission of light stimuli.It is possible that a mechanism of "gut-brain axis" in which the brain and intestine influence each other existed in the common ancestor of deuterostome animals (the blastopore becomes the anus and the mouth becomes a newly born animal).In the future, it is expected to discover a pathway in which the brain-intestinal correlation is stimulated by "light" in vertebrates such as humans, which are the same deuterostome.

Paper information:[BMC Biology] Sea urchin larvae utilize light for regulating the pylorus opening