Metabolisms of water and sodium after lateral ventricular injection of hypertonic saline in rats: a experimental study

Objective To research effects of infusing different concentrations of NaCl into the lateral ventricle on AVP(arginine vasopressin) and ANP(atrial natriuretic peptide) in plasma.Methods A stainless tube was planted into the lateral ventricle in SD rats by stereotactic technique.Five days later,the rats were divided into 3 groups,and injected 0.15 mol/L(isotonic saline,n=10),1 mol/L(hypertonic saline,n=15) and 2 mol/L(hypertonic saline,n=13) sodium chloride 10 μl into the lateral ventricle respectively in staying awake.2 ml eyeball blood sample was taken 1 h after the injection for detecting plasma AVP and ANP by radio-immunity technique.Results The mean levels of plasma AVP and ANP in two hypertonic saline(1 and 2 mol/L) groups were statistically higher than those in isotonic saline(0.15 mol/L) group.Conclusion Intracerebroventricular injection of hypertonic saline can increase the levels of AVP and ANP in plasma,suggesting that concentration of sodium is a important factor regulating metabolism of water and sodium.