TY - JOUR
T1 - Vascular and endothelial actions of inhibitors of substance P amidation
AU - Abou-Mohamed, Gamal A.
AU - Huang, Jianzhong
AU - Oldham, Charlie D.
AU - Taylor, Traci A.
AU - Jin, Liming
AU - Caldwell, Ruth B.
AU - May, Sheldon W.
AU - Caldwell, R. William
PY - 2000
Y1 - 2000
N2 - Formation of mature active neuropeptides such as substance P (SP) from their glycine extended precursors entails α-amidation of peptide precursors by the sequential enzymatic action of peptidylglycine α-monooxygenase (PAM) and peptidylamidoglycolate lyase (PGL). We reported that these two enzymes that can produce mature active neuropeptides are present in cultured bovine aortic endothelial cells (BAECs). We hypothesize that α-amidation of peptides occurs in endothelial cells and that these peptides are critically involved in the overall regulation of cardiovascular function. In this study, this hypothesis was tested using specific amidation inhibitors to determine their effects on the actions of SP and its glycine-extended precursor (SP- Gly). We have found that SP and SP-Gly are equipotent in stimulating nitric oxide (NO) release by BAECs. At 10-5 M, the specific inhibitors of PAM (4- phenyl-3-butenoic acid; PBA) and PGL (5-acetamido-2,4-diketo-6-phenyl- hexanoic acid and its methyl ester) reduced NO basal release by 40, 34, and 45%, respectively. They also reduced the production of NO induced by SP-Gly by 63, 68, and 69%, respectively, but had no effect on NO production in response to either SP or acetylcholine. SP and SP-Gly also were equipotent in relaxing rat aortic segments. The vasorelaxation to SP-Gly was endothelium dependent and inhibited by the NOS antagonist L-nitroarginine methy] ester (L. NAME), but it was not affected by inhibition of prostaglandin synthesis. Inhibitors of both PAM and PGL significantly reduced the vasorelaxihg actions of SP-Gly, whereas responses to SP were not affected. A cumulative infusion of PBA into the femoral artery of rabbits, at final concentrations of 2.4, 24, and 240 μM for 20 min each, increased the vascular resistance (VR), indicating the tonic production of vasodilating amidated peptide(s). This effect was maximum at 60 min after infusion (20.5 ± 4.7 v.s. 8.2 ± 0.7 mm Hg/ml/min; p< 0.05). These results suggest that endothelial cells can produce mature SP from its SP-Gly precursor and that a product of peptide α- amidation tonically stimulates endothelial cell NO release to control vascular tone.
AB - Formation of mature active neuropeptides such as substance P (SP) from their glycine extended precursors entails α-amidation of peptide precursors by the sequential enzymatic action of peptidylglycine α-monooxygenase (PAM) and peptidylamidoglycolate lyase (PGL). We reported that these two enzymes that can produce mature active neuropeptides are present in cultured bovine aortic endothelial cells (BAECs). We hypothesize that α-amidation of peptides occurs in endothelial cells and that these peptides are critically involved in the overall regulation of cardiovascular function. In this study, this hypothesis was tested using specific amidation inhibitors to determine their effects on the actions of SP and its glycine-extended precursor (SP- Gly). We have found that SP and SP-Gly are equipotent in stimulating nitric oxide (NO) release by BAECs. At 10-5 M, the specific inhibitors of PAM (4- phenyl-3-butenoic acid; PBA) and PGL (5-acetamido-2,4-diketo-6-phenyl- hexanoic acid and its methyl ester) reduced NO basal release by 40, 34, and 45%, respectively. They also reduced the production of NO induced by SP-Gly by 63, 68, and 69%, respectively, but had no effect on NO production in response to either SP or acetylcholine. SP and SP-Gly also were equipotent in relaxing rat aortic segments. The vasorelaxation to SP-Gly was endothelium dependent and inhibited by the NOS antagonist L-nitroarginine methy] ester (L. NAME), but it was not affected by inhibition of prostaglandin synthesis. Inhibitors of both PAM and PGL significantly reduced the vasorelaxihg actions of SP-Gly, whereas responses to SP were not affected. A cumulative infusion of PBA into the femoral artery of rabbits, at final concentrations of 2.4, 24, and 240 μM for 20 min each, increased the vascular resistance (VR), indicating the tonic production of vasodilating amidated peptide(s). This effect was maximum at 60 min after infusion (20.5 ± 4.7 v.s. 8.2 ± 0.7 mm Hg/ml/min; p< 0.05). These results suggest that endothelial cells can produce mature SP from its SP-Gly precursor and that a product of peptide α- amidation tonically stimulates endothelial cell NO release to control vascular tone.
KW - Nitric oxide synthase activity
KW - Substance P amidation
KW - Vasorelaxing action
UR - http://www.scopus.com/inward/record.url?scp=0034040528&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034040528&partnerID=8YFLogxK
U2 - 10.1097/00005344-200006000-00007
DO - 10.1097/00005344-200006000-00007
M3 - Article
C2 - 10836720
AN - SCOPUS:0034040528
SN - 0160-2446
VL - 35
SP - 871
EP - 880
JO - Journal of Cardiovascular Pharmacology
JF - Journal of Cardiovascular Pharmacology
IS - 6
ER -