Discovery
Until the early 20th century, scientists assumed that the majority of synaptic communication in the brain was electrical. However, through the careful histological examinations of Ramón y Cajal (1852–1934), a 20 to 40 nm gap between neurons, known today as the synaptic cleft, was discovered. The presence of such a gap suggested communication via chemical messengers traversing the synaptic cleft, and in 1921 German pharmacologist Otto Loewi (1873–1961) confirmed that neurons can communicate by releasing chemicals. Through a series of experiments involving the vagus nerves of frogs, Loewi was able to manually slow the heart rate of frogs by controlling the amount of saline solution present around the vagus nerve. Upon completion of this experiment, Loewi asserted that sympathetic regulation of cardiac function can be mediated through changes in chemical concentrations. Furthermore, Otto Loewi is accredited with discovering acetylcholine (ACh)—the first known neurotransmitter. Some neurons do, however, communicate via electrical synapses through the use of gap junctions, which allow specific ions to pass directly from one cell to another.
Read more about this topic: Neurotransmitter
Famous quotes containing the word discovery:
“The discovery of Pennsylvania’s coal and iron was the deathblow to Allaire. The works were moved to Pennsylvania so hurriedly that for years pianos and the larger pieces of furniture stood in the deserted houses.”
—For the State of New Jersey, U.S. public relief program (1935-1943)
“The discovery of the North Pole is one of those realities which could not be avoided. It is the wages which human perseverance pays itself when it thinks that something is taking too long. The world needed a discoverer of the North Pole, and in all areas of social activity, merit was less important here than opportunity.”
—Karl Kraus (1874–1936)
“I have known no experience more distressing than the discovery that Negroes didn’t love me. Unutterable loneliness claimed me. I felt without roots, like a man without a country ...”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 1, ch. 10 (1962)