Otto Loewi

Loewi, Otto (1873-1961) Austrian/American Physician, pharmacologist Otto Loewi was born on June 3, 1873, in Frankfurt-am-Main, Germany, to Jacob Loewi, a merchant, and Anna Willstatter. He... 

Loewi, Otto (1873-1961) German pharmacologist who proved that the nerve impulse was transferred from nerve to muscle by a chemical mediator. He distinguished acetylcholine from adrenaline for this function, and the former was later identified by Henry Dale. He shared the Nobel Prize in physiology or medicine with Dale in 1936. 

The concept of chemical neurotransmission originated in the 1920s with the classic experiments of Otto Loewi (which were themselves inspired by a dream), who demonstrated that by transferring the ventricular fluid of a stimulated frog heart onto an unstimulated frog heart he could reproduce the effects of a (parasympathetic) nerve stimulus on the unstimulated heart (Loewi Navratil, 1926). Subsequently, it was found that acetylcholine was the neurotransmitter released from these parasympathetic nerve fibers. As well as playing a critical role in synaptic transmission in the autonomic nervous system and at vertebrate neuromuscular junctions (Dale, 1935), acetylcholine plays a central role in the control of wakefulness and REM sleep. Some have even gone as far as to call acetylcholine a neurotransmitter correlate of consciousness (Perry et al., 1999). 

The concept of a neurotransmitter originated in the 1920s with the acetylcholine molecule. Henry Dale and Otto Loewi originated the concept of chemical transmission of nerve impulses. These scientists shared the 1936 Nobel Prize in Physiology or Medicine for this work. Acetylcholine was also the first neurotransmitter for which the structure was determined. Otto Loewi accomplished that task, also in 1936. 

Otto Loewi (1873-1961), professor of pharmacology at the University of Graz, awoke one night with a brilliant idea. The next day he went to his laboratory and in one of the most definitive experiments in the history of biology, brought proof of the chemical mediation of nerve impulses. 

AGerman-American physiologist, Otto Loewi discovered the first neurotransmitter, acetylcholine. Loewi was born in Frankfurt- am-Main on June 3, 1873. He attended the University of Strasbourg, from which he received his medical degree in 1896. He then worked for a period of time at University College in London, the University of Vienna, and the University of Graz (Austria). 

Henry H. Dale and Otto Loewi Physiology/Medicine Acetylcholine release at nerve endings... 

The next major step forward in deciphering the mechanisms of synaptic transmission occurred in the neuropharmacological studies of Henry Dale, Otto Loewi, Wilhelm Feldberg, and their colleagues. Although, as in the discovery of the synapse as an intercellular noncontinuous junction, many individuals contributed, Loewi is generally credited with the single decisive experiment. This is probably fair, since... 

Information transfer between two neurons or between neurons and effector cells involves the release of chemical substances, which then act on the target cell by binding to appropriate receptors embedded in the plasma membrane. This process, as originally described by Otto Loewi (Loewi 1921), is termed chemical neurotransmission and occurs at contact sites known as synapses. Neurotransmitters exert their effects via members of two major families of receptors ionotropic and metabotropic neurotransmitter receptors. Activation of ionotropic receptors leads to an increase in the ion conductance of the membrane within a time scale of milliseconds or even less, whereas activation of metabotropic receptors results in slow effects (within seconds or even minutes) which involve more or less complex signaling cascades. Accordingly, information transfer via ionotropic receptors is called fast synaptic transmission, whereas the slow counterpart is called neuromodulation (Kaczmarek and Levitan 1987). 

In 1920, the Austrian scientist Otto Loewi discovered the first neurotransmitter. In his classic experiment (which came to him in a dream), he used two frog hearts. One heart (heart 1) was placed in a chamber that was filled with saline. This chamber was connected to a second chamber that contained heart 2. Fluid from chamber 1 was allowed to flow into chamber 2. Electrical stimulation of the vagus nerve (which was attached to heart 1) caused the heart rate of heart 1 to slow down. Loewi also observed that after a delay, heart 2 also slowed down. From this experiment Loewi hypothesized that electrical stimulation of the vagus nerve released a chemical into the fluid of chamber 1 that flowed into chamber 2. He called this chemical Vagusstoff. We now know this chemical as the neurotransmitter acetylcholine. A diagram of Loewi s classic experiment is shown in Figure 11.1. 

Otto Loewi (Germany) (Nobel Prize, Medicine, 1936, chemical neurotransmission, acetylcholine) Sir John Eccles (Australia), Sir Alan Hodgkin (UK) Sir Andrew Huxley (UK) (Nobel prize, Medicine, 1963, neurotransmission, hyper- de-polarization)... 

In 1936 he shared the Nobel Prize for physiology or medicine with his friend German pharmacologist otto LOEWI for their discoveries in the chemical transmission of nerve impulses. 

Henry Hallett Dale, Otto Loewi Chemical transmission of nerve impulses... 

The understanding of depression depends on the understanding of the brain itself. This took a leap forward in 1928, when Austrian scientist Otto Loewi (1873-1961) discovered the first neurotransmitter in the brain, acetylcholine. He concluded that this substance was necessary to help electrical messages pass through the brain, from one nerve ending (neuron) to the next. It was to be another 24 years before scientists would discover the presence of other neurotransmitter substances in the brain, such as serotonin, norepinephrine and dopamine. By the 1980s, scientists isolated 40 different neurotransmitter substances in the brain. 

In 1921, an Austrian scientist, Otto Loewi, discovered ACh, the first neurotransmitter. At the time, it was difficult for neuroscientists to believe that molecules could affect neuronal activity. The principal focus was on electrical action potentials. 

---