We previously demonstrated that stimulation of proteinase-activated receptor 2 (PAR₂) by SLIGRL-NH2 elicits afferent arteriolar vasodilation, in part, by elaborating NO suggesting an endothelium-dependent mechanism. In the present study we characterized the NO-independent component of this response, using the in vitro perfused hydronephrotic rat kidney. SLIGRL-NH2 (10 µmol/L) dilated afferent arterioles pre-constricted with angiotensin II and the initial transient component of this response was resistant to NO synthase (NOS) and cyclooxygenase inhibition. This NO-independent response was not prevented by treatment with 10 nmol/L charybdotoxin and 1 µmol/L apamin, a manipulation that prevents the EDHF-like response of the afferent arteriole to acetylcholine, nor was it blocked by the addition of 1 mmol/L tetraethylammonium (TEA) or 50 µmol/L 17-octadecynoic acid, treatments that block the EDHF-like response to bradykinin. To determine if the PAR₂ response additionally involves the electrogenic Na⁺/K⁺ ATPase, responses were evaluated in the presence of 3 mmol/L ouabain. In this setting SLIGRLNH2 induced a biphasic dilation in control and a transient response following NOS inhibition. The latter was not prevented by charybdotoxin plus apamin or by TEA alone, but was abolished by combined treatment with charybdotoxin, apamin and TEA. This treatment did not prevent the NO-dependent dilation evoked in the absence of NOS inhibition. Our findings indicate a remarkable redundancy in the signaling cascade mediating PAR₂ -induced afferent arteriolar vasodilation, suggesting an importance in settings such as inflamation or ischemia, in which vascular mechanisms might be impaired and the PAR system is thought to be activated.