TY - JOUR
T1 - Adventitia-dependent relaxations of canine basilar arteries transduced with recombinant eNOS gene
AU - Tsutsui, Masato
AU - Onoue, Hisashi
AU - Iida, Yasuhiko
AU - Smith, Leslie
AU - O'Brien, Timothy
AU - Katusic, Zvonimir S.
PY - 1999/6
Y1 - 1999/6
N2 - We recently reported that expression of recombinant endothelial nitric oxide (NO) synthase (eNOS) gene in adventitial fibroblasts restores NO formation in canine cerebral arteries without endothelium in response to bradykinin ex vivo and in vivo. The present study was designed to further characterize the stimuli that can activate recombinant eNOS enzyme expressed in the adventitia of cerebral arteries. To stimulate recombinant eNOS, we used serum (0.1-10%), substance P (10-11-3 X 10-9 M), and ANG II (10- 7-10-5 M) because they increase intracellular calcium concentrations in fibroblasts. Endothelium-denuded segments of canine basilar arteries were incubated with an adenoviral vector encoding β-galactosidase gene or eNOS gene for 30 min at 37°C. After 24 h, vasomotor activity and cGMP formation in eNOS or β-galactosidase arteries were examined by isometric force recording and by radioimmunoassay, respectively. In control arteries and β- galactosidase gene-transduced arteries, serum caused concentration-dependent contractions, whereas in recombinant eNOS gene-transduced arteries, serum produced concentration-dependent relaxations. Substance P and ANG II had no effect on vascular tone in control and β-galactosidase arteries but caused concentration-dependent relaxations as well as a significant increase in cGMP levels in eNOS arteries. These relaxations were blocked by the NOS inhibitor N(G)-nitro-L-arginine methyl ester. Chemical treatment or mechanical inactivation of adventitial function significantly attenuated substance P- induced relaxations and ANG II-induced relaxations. These findings demonstrate that serum, substance P, and ANG II cause adventitia-dependent relaxations in cerebral arteries expressing the recombinant eNOS gene. This mechanism of vasodilatation may have beneficial effects in the prevention and treatment of vascular disorders characterized by the diminished bioavailability of NO, such as cerebral vasospasm.
AB - We recently reported that expression of recombinant endothelial nitric oxide (NO) synthase (eNOS) gene in adventitial fibroblasts restores NO formation in canine cerebral arteries without endothelium in response to bradykinin ex vivo and in vivo. The present study was designed to further characterize the stimuli that can activate recombinant eNOS enzyme expressed in the adventitia of cerebral arteries. To stimulate recombinant eNOS, we used serum (0.1-10%), substance P (10-11-3 X 10-9 M), and ANG II (10- 7-10-5 M) because they increase intracellular calcium concentrations in fibroblasts. Endothelium-denuded segments of canine basilar arteries were incubated with an adenoviral vector encoding β-galactosidase gene or eNOS gene for 30 min at 37°C. After 24 h, vasomotor activity and cGMP formation in eNOS or β-galactosidase arteries were examined by isometric force recording and by radioimmunoassay, respectively. In control arteries and β- galactosidase gene-transduced arteries, serum caused concentration-dependent contractions, whereas in recombinant eNOS gene-transduced arteries, serum produced concentration-dependent relaxations. Substance P and ANG II had no effect on vascular tone in control and β-galactosidase arteries but caused concentration-dependent relaxations as well as a significant increase in cGMP levels in eNOS arteries. These relaxations were blocked by the NOS inhibitor N(G)-nitro-L-arginine methyl ester. Chemical treatment or mechanical inactivation of adventitial function significantly attenuated substance P- induced relaxations and ANG II-induced relaxations. These findings demonstrate that serum, substance P, and ANG II cause adventitia-dependent relaxations in cerebral arteries expressing the recombinant eNOS gene. This mechanism of vasodilatation may have beneficial effects in the prevention and treatment of vascular disorders characterized by the diminished bioavailability of NO, such as cerebral vasospasm.
KW - Angiotensin II
KW - Bradykinin
KW - Cerebral arteries
KW - Endothelial nitric oxide synthase
KW - Gene transfer
KW - Nitric oxide
KW - Serum
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U2 - 10.1152/ajpheart.1999.276.6.h1846
DO - 10.1152/ajpheart.1999.276.6.h1846
M3 - Article
C2 - 10362662
AN - SCOPUS:0033003010
SN - 0363-6135
VL - 276
SP - H1846-H1852
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
IS - 6 45-6
ER -