Neurotransmitters, neuroregulators and neurotoxins in the life of plants

Recent evidence has shown that neurologically active compounds play an important role in the physiology of higher plants. The human neurotransmitter melatonin (N-acetyl-5-methoxytryptamine) has been found in more than 140 different plant species and is associated with flower and seed development, reproductive capacity and root growth. Hyperforin, once thought to be characteristic of St. John’s wort (Hypericum perforatum L.), has now been found in several other plant species and preliminary findings indicate that it may function as a modulator of plant cell polarity and ion flow. The excitotoxin, β-methylamino-L-alanine, has been used to selectively isolate glutamate receptor mutants in Arabidopsis, and these studies are leading to new understandings of plant cell development. The study of these and other plant neurochemicals may lead to a new understanding of plant signal transmission and the mechanisms by which plant cells sense, interpret and respond to environmental cues.