Tutin is a poisonous plant derivative found in the New Zealand tutu

Tutu (plant)

Tutu is a common name of Māori origin for plants in the genus Coriaria found in New Zealand.Six New Zealand native species are known by the name:*Coriaria angustissima*Coriaria arborea*Coriaria lurida*Coriaria plumosa...

 plant (Coriaria arborea)(Coriaria

Coriaria

Coriaria is the sole genus in the family Coriariaceae. It includes about 30 species of subshrubs, shrubs and small trees, with a widespread but disjunct distribution across warm temperate regions of the world, occurring as far apart as the Mediterranean region, southern and eastern Asia, New...

genus, several different species). It acts as a potent antagonist

Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...

 of the glycine receptor

Glycine receptor

The glycine receptor, or GlyR, is the receptor for the amino acid neurotransmitter glycine. GlyR is an ionotropic receptor that produces its effects through chloride current...

, and has powerful convulsant

Convulsant

A convulsant is a drug which induces convulsions and/or epileptic seizures, the opposite of an anticonvulsant. These drugs generally act as stimulants at low doses, but are not used for this purpose due to the risk of convulsions and consequent excitotoxicity...

 effects. It is used in scientific research into the glycine receptor, and is also sometimes associated with outbreaks of toxic honey poisoning when bees feed honeydew exudate from the sap-sucking insect commonly known as the passion vine hopper, when these vine hoppers have been feeding on the sap of tutu bushes. Toxic honey is a rare event and is more likely to occur when comb honey is eaten directly from a hive that has been harvesting honeydew from passion vine hoppers feeding on tutu plants.