Anesthesia Works on Plants Too, and We Don’t Know Why

This not only falls under the bucket of "so much we don't know" but once again shows us the richness and diversity of plant lives.  

Plants and animals are separated by 1.5 billion years of evolution, but still have many similarities. Cell structures are broadly the same, though plants add chloroplasts and cell walls to the mix. Animals evolved muscles and discrete internal organs for processing nutrients from the environment, while plant cells are more homogenous. A plant cell from one part of the organism is more similar to one from another part than two randomly selected animal cells. Other than these details and new tissue types, cells haven’t changed much in the last 1.5 billion years. That’s what, in theory, makes plants good candidates for this research. Though they may be similar in cell structure, plants are still they’re missing the major element that anesthesia shuts down in animals, neurons.

Neurons are the essential element of the nervous system and found only in animals, not plants. They transfer information about sensation and motion from peripheral parts of the body to the brain and back. By sending electro-chemical signals in the form of atomic ions, neurons can communicate great distances through the body. In someone as tall as Shaquille O’Neal, those signals travel over 8 feet, from the top of his brain to the tips of his toes. Most of this information is passed as sodium ions — atom-sized charged particles that pass through channels to zap from one neuron to the other. Lidocaine, a local anesthetic commonly used by dentists, blocks these sodium channels, stopping neurons from sending information to each other. That’s why they make your mouth numb, the neurons there can’t send pain sensations to your brain. They’re stopped.

Plants don’t have neurons, but lidocaine still deadens their movements and sensations.

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Ether and lidocaine are remarkably different chemicals, with vastly different structures, but they both work as anesthetics in plants and animals. In animals, we have some guesses about how ether works. Some results have pointed to it messing with cell membranes and somehow stopping them from communicating without completely breaking them. These membranes are layers of fat molecules that wrap every cell in our bodies, protecting them from the outside environment. It seems like ether perturbs the membranes and stops cells from communicating. Probably. But we’re not sure. Plant membranes are incredibly different though, and ether still works. It shouldn’t, but it does.

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