Effects of Limb Origin and Twenty-four Hour Storage on Contractile Response of Bovine Lateral Saphenous Vein to Norepinephrine

Authors: Klotz, James; SEVOLD, ANNA - UNIVERSITY OF KENTUCKY; BUSH, LOWELL - UNIVERSITY OF KENTUCKY; Strickland, James

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/26/2005
Publication Date: 7/24/2005
Citation: Klotz, J.L., Sevold, A., Bush, L., Strickland, J.R. 2005. Effects of Limb Origin and Twenty-four Hour Storage on Contractile Response of Bovine Lateral Saphenous Vein to Norepinephrine. Journal of Animal Science. 83:299.

Interpretive Summary: Limb differences in bovine lateral saphenous vein contractile response to norepinephrine and at twenty-four hours following dissection J. L. Klotz*1, A. C. Vevoda2, L. P. Bush2, and J. R. Strickland1 1FAPRU, USDA-ARS, Lexington, KY, 2University of Kentucky, Lexington. Vasoconstriction has been associated with several symptoms of fescue toxicosis thought to be alkaloid induced. A multi-myograph system permits rapid screening of compounds for vascular activity. However, prior to investigation of bovine vascular effects generated by tall fescue alkaloids using a myograph system, it was necessary to validate several procedural aspects. Experiments were conducted, using dose-response to norepinephrine (NE), to determine if lateral saphenous veins taken from the left limb differed from those taken from the right and to evaluate viability of tissue following 24 h storage at 2-8'C. Segments (2-3 cm) of vein were collected from both left and right legs of healthy mixed breed cattle at local abattoirs (n = 7). Tissue was placed in Krebs-Henseleit oxygenated-buffer and kept on ice or stored at 2'8'C until used. Veins were trimmed of excess fat and connective tissue, sliced into 2-3 mm sections and suspended in a myograph chamber containing 5 mL of oxygenated Krebs-Henseleit buffer (95% O2/5% CO2; pH = 7.4; 37'C). Tissue was allowed to equilibrate at 1 g of tension for 1.5 h prior to addition of NE. Increasing doses of NE were administered every 15 min following buffer replacement. Data were normalized as a percent of contractile response induced by maximal dose of NE (5x10-4M) for profiling. Veins from both left and right limbs demonstrated contractions in a dose-response manner (P < 0.01), but did not differ between limbs. There were no differences in dose-response to NE between tissue tested the day of dissection and tissue exposed 24 h later. Maximal contractile response to NE did not differ between day for left (d1 = 20.1; d2 = 15.8 g; SE = 3.9) or right limbs (d1 = 18.2; d2 = 15.1 g; SE = 2.4). Limb of origin and overnight storage of tissue did not appear to effect tissue responsiveness to NE. Thus, future experiments will not be limited to a single limb and experiments can be extended beyond day of dissection. bovine, saphenous vein, dose-response, norepinephrine

Technical Abstract: Limb differences in bovine lateral saphenous vein contractile response to norepinephrine and at twenty-four hours following dissection J. L. Klotz*1, A. C. Vevoda2, L. P. Bush2, and J. R. Strickland1 1FAPRU, USDA-ARS, Lexington, KY, 2University of Kentucky, Lexington. Vasoconstriction has been associated with several symptoms of fescue toxicosis thought to be alkaloid induced. A multi-myograph system permits rapid screening of compounds for vascular activity. However, prior to investigation of bovine vascular effects generated by tall fescue alkaloids using a myograph system, it was necessary to validate several procedural aspects. Experiments were conducted, using dose-response to norepinephrine (NE), to determine if lateral saphenous veins taken from the left limb differed from those taken from the right and to evaluate viability of tissue following 24 h storage at 2-8'C. Segments (2-3 cm) of vein were collected from both left and right legs of healthy mixed breed cattle at local abattoirs (n = 7). Tissue was placed in Krebs-Henseleit oxygenated-buffer and kept on ice or stored at 2'8'C until used. Veins were trimmed of excess fat and connective tissue, sliced into 2-3 mm sections and suspended in a myograph chamber containing 5 mL of oxygenated Krebs-Henseleit buffer (95% O2/5% CO2; pH = 7.4; 37'C). Tissue was allowed to equilibrate at 1 g of tension for 1.5 h prior to addition of NE. Increasing doses of NE were administered every 15 min following buffer replacement. Data were normalized as a percent of contractile response induced by maximal dose of NE (5x10-4M) for profiling. Veins from both left and right limbs demonstrated contractions in a dose-response manner (P < 0.01), but did not differ between limbs. There were no differences in dose-response to NE between tissue tested the day of dissection and tissue exposed 24 h later. Maximal contractile response to NE did not differ between day for left (d1 = 20.1; d2 = 15.8 g; SE = 3.9) or right limbs (d1 = 18.2; d2 = 15.1 g; SE = 2.4). Limb of origin and overnight storage of tissue did not appear to effect tissue responsiveness to NE. Thus, future experiments will not be limited to a single limb and experiments can be extended beyond day of dissection. bovine, saphenous vein, dose-response, norepinephrine