Instructions: Given a passage classify if the passage has a definite objective/aim/goal or not. Output '1' if the passage has a defininte objective/aim/goal and output '0' if the passage does not have a definite objective/aim/goal.
Input: Marinobufagenin (MBG) promotes natriuresis via inhibition of renotubular Na/K-ATPase (NKA) and causes vasoconstriction via inhibition of vascular NKA. Atrial natriuretic peptide (ANP), via cyclic guanosine monophosphate (cGMP)/protein kinase G (PKG)-dependent mechanism, sensitizes renal NKA to MBG but reduces MBG-induced inhibition of vascular NKA. As aging is associated with a downregulation of cGMP/PKG signaling, we hypothesized that in older rats, ANP would not potentiate renal effects of MBG and would not oppose vascular effects of MBG.', 'In younger (3-month-old) and older (12-month-old) Sprague-Dawley rats, we compared SBP, natriuresis, activity of NKA in aorta and renal medulla, and levels of MBG and -ANP at baseline and following acute NaCl loading (20%, 2.5ml/kg, intraperitoneally), and studied modulation of MBG-induced NKA inhibition by -ANP in vitro.', 'As compared with younger rats, NaCl-loaded older rats exhibited a greater MBG response, greater SBP elevation (25 vs. 10mmHg, P<0.01) and greater inhibition of NKA in aorta (39 vs. 7%, P<0.01), 30% less natriuresis, and less inhibition of renal NKA (25 vs. 42%, P<0.05) in the presence of comparable responses of -ANP and cGMP. In aorta and kidney of older rats, the levels of PKG were reduced, the levels of phosphodiesterase-5 were increased compared with that in young rats, and -ANP failed to modulate MBG-induced NKA inhibition.
Output:
0