Drinking behavior in the spiny mouse ( Acomys cahirinus) following putative dipsogenic challenges

Abstract

Male spiny mice ( Acomys cahirinus) were challenged with several putative dipsogenic stimulus conditions: hypertonic sodium chloride (NaCL), 24-h water deprivation, d, l-isoproterenol HCl, angiotensin II (AII) and polythylene glycol (PEG), or control conditions, in within-subjects designs. Water intake and drinking pattern were monitored electronically in the home cage over a 2–6-h test period without food present, during the light portion of the L/D cycle. In addition, hematocrits were measured following several treatments and mean arterial blood pressure was monitored in response to several doses of AII. As expected, both water deprivation and hypertonic NaCl led to robust drinking with short latencies. PEG was also an effective dipsogen; while quite variable, latencies were often shorter than are typically reported for the rat. Isoproterenol induced a modest, but significant, dose-related drinking. Interference by AII's prominent pressor action might account, at least in part, for its relative ineffectiveness as a dipsogen. Comparisons are made with other rodent species similarly challenged.