ANOVA showed no significant differences between treatments for 0.3 M NaCl intake [F(3, 12) = 3.0; P > 0.05] or water intake [F(3, 12) = 4.0; P > 0.05] in fluid replete rats or between treatments for 0.3 M NaCl intake [F(3, 15) = 0.9; P > 0.05] or water intake [F(3, 15) = 3.3; P > 0.05] in FURO + CAP-treated rats that

received injections in sites outside the LPBN. Misplaced injections were ventral (MPBN), dorsal or rostral to the LPBN. Some rats had unilateral KRX-0401 price injections partially into the LPBN. Similar to previous results (Callera et al., 2005 and De Oliveira et al., 2007), the present study shows that bilateral injections of muscimol (GABAA receptor agonist) into the LPBN induce hypertonic NaCl and water ingestion in fluid replete rats (untreated rats) and increase 0.3 M NaCl intake in FURO + CAP-treated rats. The involvement of GABAA receptors of the LPBN in the control

of water and NaCl intake is supported by a previous study showing that the GABAA receptor antagonist bicuculline injected into the LPBN completely blocked water and hypertonic NaCl intake induced by muscimol, which suggests that muscimol activates LPBN GABAA receptors to increase sodium intake (Callera et al., 2005). The present results extend the conclusions of the previous study by showing that pretreatment of the LPBN with bilateral injections of the nonpeptide AT1 receptor antagonist losartan reduce water and 0.3 M NaCl intake caused by muscimol injected into the same site

in fluid replete rats, as well as the MEK inhibitor increase in 0.3 M NaCl produced by muscimol injected bilaterally into the LPBN in FURO + CAP-treated rats. Injections of losartan alone into the LPBN did not change water or 0.3 M NaCl intake by untreated rats or FURO + CAP-treated rats. Results from rats with misplaced injections confirm that muscimol effects on water and 0.3 M NaCl intake are specific to the LPBN. The results also suggest that angiotensinergic mechanisms in the LPBN are essential for the dipsogenic and natriorexigenic responses induced by the blockade of LPBN neurons with muscimol in fluid replete rats or the increase in the natriorexigenic responses produced by muscimol injected into the LPBN in FURO + CAP-treated rats. Pretreatment with losartan into the LPBN reduced Phosphoprotein phosphatase muscimol effects on water and/or NaCl intake by fluid replete or FURO + CAP-treated rats. Therefore, if endogenous GABA release in the LPBN was important for FURO + CAP-induced water and sodium intake, similar effects would be expected when losartan alone was injected in FURO + CAP-treated rats. However, injections of losartan alone did not modify FURO + CAP-induced water or NaCl intake, suggesting that GABA release or its interaction with activated AT1 receptors in the LPBN is not essential for sodium or water intake induced by FURO + CAP.