Laurent DescarriesClaude Lacasse, University of MontrealOne of Canada’s leading neuroscientists, the University of Montreal’s Laurent Descarries, passed away this fall (October 3) at the age of 73. Descarries was internationally renowned for his extensive work on the ultrastructural organization of axon terminals established in the brain by neurons using the chemical messengers dopamine, noradrenaline, serotonin, and acetylcholine. In particular, his work demonstrated their mostly asynaptic character, meaning that they typically do not establish classic synapses with clearly defined postsynaptic specializations. Instead, these neurons are now thought to mediate their signals through a process called “diffuse transmission” or “volume transmission,” in which the neurotransmitters they release act at more distant receptors within a certain area around the releasing axon terminal.
Initially trained as an MD and neurologist, Descarries began his research career during a fellowship at the Massachusetts General Hospital of Harvard University in Boston in 1963. During this period, he worked with neurologist Otto Appenzeller on peripheral nervous system dysfunctions associated with cerebrovascular diseases such as stroke, which disrupt circulation in the brain. He then pursued his training in neuroanatomy with the renowned anatomist Bernard Droz at the Center for Nuclear Research of Saclay in France, with whom he contributed to the popularization of the use of autoradiography, in combination with electron microscopy, to examine the structure of axon terminals and synapses of different types of neurons. Using this technique, he was able to show for the first time that the axon terminals of ...
