Vasodilator activity in extracts of various regions of the central nervous system

Geoffrey Wingfield Harris, 1913-1971

Geoffrey Wingfield Harris was born in Acton, London on 4 June 1913; the father’s family came from Oxfordshire, his mother, Winifred Irene Stiles, from Buckinghamshire. Geoffrey Harris’s paternal grandfather, Thomas Harris, had become headmaster of an L.C.C. school (Warlington Road School, Westbourne Park) at the early age of 24; this achievement had been made possible by his mother’s hard work and careful saving for the purpose of giving her children a good education. Such self-denial by Geoffrey Harris’s great-grandmother repeated itself in the next but one generation: both Geoffrey’s parents saved strenuously to give him and his younger sister the best possible training. Geoffrey’s father, Tom Harris, had won a scholarship to study physics at the Royal College of Science, S. Kensington, spent 2 years in Cambridge as a research student of J. J. Thompson, and 9 years as a lecturer at East London College, University of London. He was then appointed to the Ballistics Department, Woolwich Arsenal, a post he held till his death in 1942. His special line was the photography of bullets as they emerge from a rifle; the results were confidential and remain unpublished, but appear to have been of the highest quality. Geoffrey’s devotion and gratitude to his father have been an important factor in his life.

Micro-iontophoretic studies on neurones in the cuneate nucleus

1. Cuneate cells in anaesthetized cats were strongly excited by L-glutamate, and somewhat less by D-glutamate; cells which receive afferents from hair receptors were particularly sensitive.2. Glutamate could be used to demonstrate post-synaptic inhibitory inputs from the dorsal column, the medial lemniscus and the frontal cortex.3. Many cuneate cells were also strongly excited by adenosinetriphosphate (ATP); this was probably due to the chelating action of ATP, as citric acid was also quite effective.4. gamma-Aminobutyric acid (GABA) readily blocked all forms of spontaneous and evoked activity, except antidromic invasion of cuneothalamic neurones; cells which receive proprioceptive afferents were particularly sensitive to GABA. Glycine had a comparable effect.5. Acetylcholine (ACh), catecholamines, histamine, 5-hydroxytryptamine (5-HT) and an extract containing substance P mostly had only weak depressant actions. Cholinergic and mono-aminergic mechanisms are probably not very significant in the cuneate.6. These results are consistent with the possibility that glutamate and GABA (or glycine), or some closely related compounds, are the main excitatory and inhibitory transmitters in the cuneate nucleus.7. If ATP is released from afferent nerve endings, it could also play a significant role in excitation.