Sympatho-excitatory and hypertensive responses to central infusion of Na⁺ rich aCSF are enhanced by aldosterone and mediated by mineralocorticoid receptors (MR) and benzamil blockable Na⁺ influx leading to "ouabain" release and AT1-receptor stimulation. The present study evaluated the functional role of these mechanisms in the paraventricular nucleus (PVN). In conscious Wistar rats, Na⁺ rich aCSF was infused either directly into the PVN or intracerebroventricularly (icv) preceded by aldosterone and blockers. Infusion of Na⁺ rich aCSF in the PVN caused gradual increases in BP and HR. Aldosterone and a subpressor dose of ouabain in the PVN alone did not affect BP and HR, but enhanced responses to Na⁺. Eplerenone, benzamil and "ouabain"-binding Fab fragments only blocked the enhancement by aldosterone, whereas losartan blocked all responses to Na⁺ rich aCSF in the PVN. Increases in BP and HR by icv infusion of Na⁺ rich aCSF were enhanced by aldosterone infused icv, but not in the PVN. Telmisartan in the PVN blocked again all responses. In contrast, both eplerenone and benzamil in the PVN did not change the pressor responses to icv infusion of aldosterone and Na+ rich aCSF. These findings indicate that AT1-receptors in the PVN mediate the responses to Na⁺ rich aCSF, and their enhancement by aldosterone both locally in the PVN or in the general CSF. MR, benzamil blockable Na⁺ channels or transporters and "ouabain" can be functionally active in the PVN, but in Wistar rats appear not to contribute to the pressor responses to short-term increases in CSF [Na⁺].