“Reactivated memory is enhanced by water shortage, through angiotensin II, during reconsolidation”

LIA FRENKEL, BEATRIZ DIMANT, HANS IMBODEN, HECTOR MALDONADO AND ALEJANDRO DELORENZI

en San Diego, California, Estados Unidos.

Conferencia; 34th Annual Meeting Society for Neuroscience, 23 al 27 de octubre, 2004; 2004

Angiotensin II (ANGII) is a coordinator of multiple functions that, triggered by water shortages, keeps water homeostasis. Brain levels of ANGII increase when crabs of the species Chasmagnathus are water deprived. Previous works in this crab showed that consolidation, retrieval and- more recently- reconsolidation of contextual fear memory are enhanced by a contingent episode of water deprivation, through ANGII. The complete neural basis of this context fear memory are still unknown but some neurons that support it were identified (Tomsic et al., 2004); they were called Moving Detector Neurons (MDN) and are located in the lobula, at the optic lobe. The main objective of this work is to disclose the neural basis of the ANGII-memory enhancing system in the crab’s brain. A second objective is to establish the pattern of ANGII-distribution in the brain in different physiological states. By the use of immunohistochemistry against ANGII and a confocal microscope we will describe the ANGII-distribution pattern in the optic lobe and supraesophagial ganglia of the crab. After a reliable analysis we will be able to establish relationships between ANGII distribution and its different physiological functions (with the primarily focus on memory modulation). The first results shows that (1) this multifunctional signal is widespread distributed in the brain and (2) MDN contain ANGII suggesting that they release the memory-enhancer neuropeptide during water deprivation.