Intravenous administration of ovokinin(2-7), a cleavage peptide derived from ovalbumin, dose-dependently (0.1-5 mg/kg) lowered the mean arterial pressure (MAP) that was not accompanied by a significant change in the heart rate (HR) of urethane-anesthetized rats. The hypotensive effects of ovokinin(2-7) were five orders of magnitude lower compared to that of bradykinin and were largely prevented by pretreatment with the bradykinin B2 receptor antagonist HOE140 (81.6±18.4%) and moderately affected by the B1 receptor antagonist [des-Arg10]-HOE140 (26.3±15.5%). Intracellular Ca2+ levels, as measured by Fur 2-AM, were significantly elevated in cultured aorta smooth muscle cells by ovokinin(2-7). The increases were abolished by HOE140 and unaffected by [des-Arg10]-HOE140. The elevation of intracellular Ca2+ by ovokinin(2-7) was dependent on Ca2+ entry from extracellular space as it was reduced in a Ca2+-free solution. Pretreatment of the cells with the phospholipase C inhibitor U73122 (2 μM) eliminated the Ca 2+ increase by the peptide. PA phosphohydrolase and phospholipase A2 inhibitors significantly reduced the responses as well. Our results show that ovokinin(2-7) modulates cardiovascular activity by interacting with B2 bradykinin receptors.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etsu-works-19930 |
| Date | 15 August 2004 |
| Creators | Scruggs, Phouangmala, Filipeanu, Catalin M., Yang, Jun, Chang, Jaw Kang, Dun, Nae J. |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | ETSU Faculty Works |
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