CONICET | Buscador de Institutos y Recursos Humanos

Angiotensins neuropeptides appear to emerge early in evolution. Their classical osmoregulatory functions in vertebrates have been shown in some invertebrates. Our results in the euryhaline and semiterrestrial crab Chasmagnathus granulatus, led us to demonstrate that water deprivation triggers an increased brain angiotensin II-like immunoreactivity (ANGII-ir), which improves memory processes through ANGII receptors. We suggested that the release of brain angiotensins in response to water shortages would be an ancient mechanism for coordinating different functions that together would enable organisms to cope with this environmental change. Here, our working hypothesis is that angiotensinergic neuropils will have their own dynamics when animals are confronted to water deprivation. We first described the neuroanatomic distribution of ANGII-like neuropeptide. Our results indicate that ANGII-ir is strongly expressed in specific neuronal processes of all major areas, comprising the three optic neuropils, medulla terminalis and hemiellipsoid body, and the proto-, deuto- and tritocerebrum of supraesophageal ganglia, especially in the medial protocerebrum containing the central body. Secondly, we evaluated the physiological changes in ANGII-like level in different brain neuropils for water-deprived crabs. We found a decrease in ANGII-ir after 2 hours of water deprivation in the olfactory neuropil but an increase in the central body that returned to the basal level after 6 hours. In addition, after 6 hours of deprivation we found a profound decrease in ANGII-ir in several brain areas. These results suggest that several functions are regulated by this neuropeptide while animals are coping with water-shortages.