Henry Hallett Dale - Research

Research

Although Dale and his colleagues first identified acetylcholine in 1914 as a possible neurotransmitter, Loewi showed its importance in the nervous system. The two men shared the 1936 Nobel Prize for Medicine.

During the 1940s Dale was embroiled in the scientific debate over the nature of signaling at the synapse. Dale and others believed that signaling at the synapse was chemical, while John Carew Eccles and others believed that the synapse was electrical. It was later found that most synaptic signalling is chemical, but there are some synapses that are electrical.

Dale also originated the scheme used to differentiate neurons according to what neurotransmitter they release. Thus, neurons releasing norepinephrine (also known as noradrenaline) are called noradrenergic, neurons releasing GABA are GABAergic, and so on. This scheme is related to Dale's principle (sometimes erroneously referred to as Dale's Law). This principle states that each neuron releases only one type of neurotransmitter. Dale's principle has been shown to be false; since many neurons have been shown to release neuropeptides and amino acids in addition to classical neurotransmitters such as acetylcholine or biogenic amines (Bear, et al. 2001). This finding, that numerous neurotransmtters can be released by the same neuron, is referred to as the "coexistence principle." This phenomenon was most popularized by the Swedish neuroanatomist and neuropharmacologist Tomas Hökfelt, who is considered to be the "Father of the Coexistence Principle."