Area Postrema - History of Research

History of Research

The area postrema was first named and located in the gross anatomy of the brain by Magnus Gustaf Retzius, a Swedish anatomist, anthropologist and professor of histology at the Karolinska Mediko-Kirurgiska Institutet in Stockholm. In 1896, he published a two-volume monograph on the gross anatomy of the human brain in which the area postrema was mentioned. This work was one of the most important works published in the 19th century on the anatomy of the human brain.
In 1937, a publication by King, L.S. claimed that the area postrema was made up solely of glial cells, but this was later disproved by the research of several scientists including Jan Cammermeyer, Kenneth R. Brizzee and Herbert L. Borison, who demonstrated the presence of neurons in the area postrema of several mammal species.
Scientists became increasingly interested in the research of vomiting in the 1950s, perhaps in part due to society's heightened awareness of radiation sickness, a condition in which many patients having vomited after radiation exposure died. Intensive studies on vomiting began in the 1950s at the University of Utah College of Medicine, where Borison held a strong presence as both a professor and a researcher. He had received his doctorate in 1948 from Columbia University, establishing himself as an authority on brainstem and neurophysiology. Prior to the research of Borison and his well-known colleague S.C. Wang, a doctor and assistant professor from Columbia University, it was believed that the human body's chemodetection and coordination of vomiting, or emesis, were controlled exclusively by the dorsal vagal nucleus. Yet this idea was "incompatible with the observation that emesis could still be induced by gastrointestinal irritants in dogs with chronic lesions of the dorsal vagal nucleus", and so Borison and Wang dedicated their research to solving this puzzle. Borison eventually explained that their results showed the existence of two areas in the brain related to emesis; one, a chemosensor for vomiting with no coordinating function, located in the fourth ventricle and two, a coordinator of vomiting with no chemosensory function, located in the lateral reticular formation of the medulla oblongata.
In 1953, Borison and Wang determined that the chemosensor area acted as a vomiting trigger zone in the brain stem, which they named the chemoreceptor trigger zone (CTZ) for emesis. Using cats and dogs as model organisms, they found that the removal of this trigger zone from the brain allowed for the prevention of emesis in the animals directly following injection of certain chemicals into the blood stream, demonstrating the existence of a relationship between the trigger zone and the act of vomiting. The CTZ was anatomically located in the area postrema of the medulla oblongata. The area postrema had been anatomically identified and named nearly 60 years earlier, but its function had remained unknown until the work of Borison and Wang proposed its role in emesis, which was later confirmed by many laboratories.
Other scientists noted as pioneers in the field of research concerning the area postrema and the mechanism of vomiting in general are Larry McCarthy, A.D. Miller and V. J Wilson.