The Central Hypotensive Effect Of Salusin-β Is Partly Mediated By Nitric Oxide

Background Salusins are newly identified bioactive peptides, of 28 and 20 amino acid residues, respectively, exsiting widely in hematopoietic system, endocrine system and central nervous system (CNS). Salusins have been shown to exert a variety of functions in the cardiovascular, endocrine and immune systems. Although it has been proved that salusin-βdistributed widely in CNS, the cardiovascular function of central salusin-βis unclear. Objective To study the central cardiovascular effects of salusin-P by injection of salusin-βinto lateral cerebral ventricle (LCV) in anesthetic and artificially respiratory rats. Methods Fifty seven anesthetized, paralyzed male SD rats were employed in present study. Twenty five of them were randomized into control group (aCSF, n=4), salusin-β100 pmol group (n=7), salusin-P 200 pmol group (n=7), and salusin-β400 pmol group (n=7).Salusin-β(100,200 or 400 pmol) or aCSF was injected into LCV to observe their central cardiovascular effects of central salusin-β. Another thirty two rats, MK-801 (n=7),L-NAME(n=7),Bic(n=7), salusin-a (n=7) or aCSF (n=4) was prior applied into LCV of rats 10 min before salusin-P (200 pmol) was injected. Results LCV injection of salusin-βproduced a significant decrease in BP (salusin-β100 pmol:99±16 vs.85±16 mmHg, P<0.05; salusin-β200 pmol:97±8 vs.82±9 mmHg, P<0.05; salusin-β400 pmol:86±21 vs. 73±29 mmHg, P<0.05), but produced no significant influence in HR of rats. LCV injection of aCSF didn't alter BP or HR in anesthetized rats. The hypotension induced by LCV injection of salusin-βwas significantly inhibited by pretreatment with central application of eNOS inhibitor L-NAME (-6±10 vs.-17±16 mmHg, P<0.05), but not by prior injection of MK-801,Bic or salusin-a. Conclusion Our present study shows that LCV injection of salusin-βproduces hypotension of rats, which is partly mediated by nitric oxide.