Role of protein kinase g in nitric oxide and cgmp-induced
relaxation of newborn ovine pulmonary veins.
Gao, Yuansheng, Srinivas Dhanakoti, Jean-Francois Tolsa, and J. Usha
Raj.
Department of Pediatrics, Harbor-UCLA Medical Center, University of
California, Los Angeles, School of Medicine, Torrance, CA 90509
APStracts 6:0243A, 1999.
In a variety of systemic blood vessels, protein kinase G (PKG) plays a
critical role in mediating relaxation induced by agents which elevate
guanosine 3',5'-cyclic monophosphate (cGMP) such as nitric oxide,.
The role of PKG in nitric oxide and cGMP-induced relaxation is less
certain in the pulmonary circulation. In the present study, we
examined the effects of inhibitors of PKG on the responses of
isolated fourth generation pulmonary veins of newborn lambs (10+/-1
d) to nitric oxide and cGMP. In vessels preconstricted with
endothelin-1, nitric oxide and 8-BrcGMP (a cell membrane permeable
cGMP analog) induced concentration-dependent relaxation. The
relaxation was significantly attenuated by Rp-8-Br-PET-cGMPS (a PKG
inhibitor) and H-8 [an inhibitor of PKG and protein kinase A (PKA)]
but not affected by KT5720 (a PKA inhibitor). Biochemical study
showed that PKG activity in newborn ovine pulmonary veins was
inhibited by 8-Br-PET-cGMPS and H-8 but not by KT5720. PKA activity
was not affected by 8-Br-PET-cGMP but was inhibited by H-8 and
KT5720. These results suggest that PKG is involved in relaxation of
pulmonary veins of newborn lambs induced by nitric oxide and cGMP.
Received 30 October 1998; accepted in final form 24 May 1999.
APS Manuscript Number A988-8.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 14 June 1999