Area Postrema - Current Research

Current Research

Research has continued today around the world on the functions of the area postrema. Beyond its role in emesis, as studied intensely by the researchers of the mid-1900s, the activity of the area postrema has been closely linked to other autonomic functions such as regulation of food intake, body fluid homeostasis, and cardiovascular regulation through behavioral studies and electrophysiological studies. In 2007 in Japan, research was performed on the mechanism of excitability of area postrema neurons by extracellular ATP. Voltage clamp whole-cell recording techniques were used on rat brain slices. The results showed that most responses to ATP are excitatory and that they are mediated by particular P2 purinoceptors found in the area postrema. The role of the area postrema in flavor-conditioned aversion and preference was studied in 2001 by researchers at the Brooklyn College at the City University of New York. The experiment tested the effect of area postrema lesions in rats on their ability to learn flavor-conditioned aversion to flavors paired with toxic drug treatments, which indeed showed that lesions of the area postrema leads to impaired flavor aversion learning. A 2009 study followed the development of the area postrema, using a macaque monkey model in an attempt to identify and characterize neurotransmission in this region as well as to resolve outstanding incongruities across research. These scientists found, in culmination, that previous studies suggest noradrenalin and/or dopamine cause CA fluorescence in the area postrema macaque-CA, meaning catecholaminergic or derived from an amine and functioning as a neurotransmitter or hormone or both. The study, however, found evidence of neurotransmitter secretion instead of release in vesicles. Also, their findings concluded GABA is a major neurotransmitter in the area postrema, not glutamate. Ongoing research continues to unravel discrepancies among various rat, cat, and now macaque monkey models of research.