Recently it was demonstrated that plasma hyperosmolarity, a classic dipsogenic stimulus, can also facilitate sodium intake if inhibitory mechanisms are deactivated by the injections of moxonidine (α2-adrenoceptor/imidazoline receptor agonist) into the lateral parabrachial nucleus (LPBN). It has also been suggested that water intake induced by plasma hyperosmolarity depends on the activation of central cholinergic mechanisms. Therefore, in the present study, we investigated whether central cholinergic mechanisms are important for water and sodium intake by hyperosmotic rats treated with moxonidine into the LPBN. Male Holtzman rats (290-310 g, n = 9) were anesthetized with ketamine (80 mg/kg of body weight) and xylazine (7 mg/kg of body weight) subcutaneously and stainless steel guide-cannulas were implanted into the lateral ventricle (LV) and bilaterally into the LPBN. Five days after the brain surgery, the animals received an intragastric load of 2 M NaCl (2 ml) and an injection of saline or atropine (muscarinic antagonist; 20 nmol/1 µl) in the LV. Forty-five minutes later, the animals received bilateral injections of vehicle or moxonidine (0.5 nmol/0.2 µl) into the LPBN. Water and 0.3 M NaCl intake was measured for 2 h starting 15 min after LPBN injections. Results are reported as mean ± SEM. Two-way ANOVA using treatments and times as factors followed by Newman-Keuls tests was used for comparisons. Bilateral injections of moxonidine into the LPBN of hyperosmotic rats that received saline in the LV significantly increased water (13.0 ± 4.4 ml/2 h, vs. vehicle: 6.9 ± 1.0 ml/2 h, p < 0.05) and 0.3 M NaCl intake (18.6 ± 5.2 ml/2 h, vs. vehicle: 0.2 ± 0.1 ml/2 h, p < 0.05). The pre-treatment with atropine into the LV abolished water (0.7 ± 0.3 ml/2 h, p < 0.05) and 0.3 M NaCl intake (1.3 ± 0.4 ml/2 h, p < 0.05) induced by hyperosmolarity combined with moxonidine injected into the LPBN. The results suggest the involvement of central cholinergic muscarinic mechanisms on water and sodium intake by hyperosmotic rats treated with moxonidine injected into the LPBN.