Otto Loewi - Research

Research

Before Loewi's experiments, it was unclear whether signalling across the synapse was bioelectrical or chemical. Loewi's famous experiment, published in 1921, largely answered this question. According to Loewi, the idea for his key experiment came to him in his sleep. He dissected out of frogs two beating hearts: one with the vagus nerve which controls heart rate attached, the other heart on its own. Both hearts were bathed in a saline solution (i.e. Ringer's solution). By electrically stimulating the vagus nerve, Loewi made the first heart beat slower. Then, Loewi took some of the liquid bathing the first heart and applied it to the second heart. The application of the liquid made the second heart also beat slower, proving that some soluble chemical released by the vagus nerve was controlling the heart rate. He called the unknown chemical Vagusstoff. It was later found that this chemical corresponded to Acetylcholine (Kandel, et al. 2000).

Loewi's investigations “On an augmentation of adrenaline release by cocaine” and “On the connection between digitalis and the action of calcium” were profound concepts and were studied relentlessly by others decades later.

He also clarified two mechanisms of eminent therapeutic importance: the blockade and the augmentation of nerve action by certain drugs.

He is almost as famous for the means by which the idea for his experiment came to him as he is for the experiment itself. On Easter Saturday 1923, he dreamed of an experiment that would prove once and for all that transmission of nerve impulses was chemical, not electrical. He woke up, scribbled the experiment onto a scrap of paper on his night-stand, and went back to sleep.

The next morning he arose very excited because he knew this dream had been very important. But he found, to his horror, that he couldn't read his midnight scribbles. That day, he said, was the longest day of his life, as he could not remember his dream. That night, however, he had the same dream. This time, he immediately went to his lab to perform the experiment. From that point on, the consensus was that the Nobel was not a matter of "if" but of "when."

Thirteen years later, Loewi was awarded the Nobel Prize in Physiology or Medicine, which he shared with Sir Henry Hallett Dale.