Endothelin-1 and nitric oxide affect human cerebromicrovascular endothelial responses and signal transduction.
Endothelium plays a central role in regulating the vascular tone, blood flow and blood brain barrier (BBB) permeability. The experiments presented here examine the mechanisms by which nitric oxide (NO) and endothelin-1 (ET-1) may be involved in these processes. The findings indicate that ET-1-stimulated [Ca2+]i accumulation occurs through activation of ETA receptor. The capacity of NO to affect this response was indicated by results showing: 1) a two-fold increase in ET-1-stimulated [Ca2+]i by L-NAME, the inhibitor of nitric oxide synthase, and 2) a dose-dependent decrease in [Ca2+]i accumulation by pretreatment with Nor-1 (NO donor). Abrogation of this Nor-1 effect by ODQ (an inhibitor of guanylyl cyclase) or Rp-8-pCPT-cGMPS (an inhibitor of protein kinase G) and inhibition of ET-1 stimulated intracellular Ca2+ accumulation by 8-bromo-cGMP (a permeable, analog of cGMP) substantiate the involvement of interplay between ET-1 and NO in [Ca2+]i accumulation in HBMEC. ET-1 treatment also increased thickness of F-actin cytoskeletal filaments in HBMEC. This effect was attenuated by pretreatment with NO; NO also rarefied F-actin filaments in control cultures. The findings support a linkage between NO and ET-1 in regulating microvascular tone, microcirculation and BBB permeability and indicate a role for cGMP/cGMP protein kinase system and cytoskeletal changes in responses of HBMEC.
Chen
Y
Y
Naval Medical Research Center, Bethesda, MD, USA.
McCarron
R M
RM
Azzam
N
N
Bembry
J
J
Reutzler
C
C
Lenz
F A
FA
Spatz
M
M
D000199:Actins / Q000502:physiology; D001812:Blood-Brain Barrier / Q000502:physiology*; D001921:Brain / Q000098:blood supply*; D001929:Brain Edema / Q000503:physiopathology*; D002118:Calcium / Q000378:metabolism; D002199:Capillary Permeability / Q000502:physiology; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000502:physiology*; D004730:Endothelium, Vascular / Q000503:physiopathology*; D006801:Humans; D008833:Microcirculation / Q000503:physiopathology; D009569:Nitric Oxide / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D000199:Actins; D019332:Endothelin-1; D009569:Nitric Oxide; D002118:Calcium