IT MAY be possible to get morphine’s painkilling effects without having to
take ever larger doses鈥攁nd, possibly, without risking withdrawal symptoms.
The finding turns conventional theories on their head.
Morphine kills pain by mimicking the body’s natural opiates, binding to
special ised receptors on nerve cells. When natural opiates bind to them, the
receptors are sucked inside the cell鈥攁 process called
endocytosis鈥攁nd then return to the cell surface. But when morphine binds
to the receptors, it blocks endocytosis.
This was thought to prolong morphine’s effect and give it its power. “It
seemed like the last thing you’d…
