Maternal RAS influence on the ontogeny of thirst

Perillan, C., Costales, M., Vijande, M., and J. Arguelles. Maternal RAS influence on the ontogeny of thirst. Physiol Behav XX (X) 000-000, 2006. The main objective of this study was to investigate the effect of an altered ambiance in utero, on the development of thirst mechanisms in the offspring. Female rats underwent a partial ligature of the aorta (PAL), which induces an intrinsic activation of the renin angiotensin system (RAS), thirst and sodium appetite. A second group of female rats was treated with desoxycorticosterone (DOCA) which depresses the RAS. The offspring of these two groups were tested for their responses to several thirst stimuli at 2, 4 and 6 days of age. The offspring from PAL mothers responded like their controls to cellular dehydration (NaCl hypertonic injection) at 2 days of age, and also did to extracellular dehydration by polyethyleneglycol at 4 days. Nevertheless, they responded more to isoproterenol at 6 days of age in comparison to their control group. The offspring from DOCA treated mothers did not show statistically significant responses (in comparison with vehicle injected pups) to hypertonic NaCl at two days nor to polyethyleneglycol at four days. Water intake at 6 days of age after isoproterenol administration in DOCA was statistically enhanced, but not differently from the response obtained from pseudo-DOCA treated pups. In particular, rats developed in a hypereninemic ambiance (O-PAL) during gestation, responded with higher water intake when treated with a strong RAS and thirst activator (isoproterenol) but responded normally to a more gentle and complex stimulus (PG). Therefore it seems that in utero conditions can determine the chronology and intensity of thirst responses in offspring.