Tyrosine enteroreceptor of Hydra: its function in eliciting a behavior modification.

Hydra that still contain partially digested food in their gastrovascular cavities, undergo a modified feeding response when they ingest additional prey. A localized constriction is formed just below the sites of tentacle attachment, preventing the loss of gastrovascular contents. This response involves the interaction of an ectodermal receptor system for glutathione and an endodermal receptor system for tyrosine.