Rho kinase activation and ROS production contributes to the cooling enhanced contraction in cutaneous equine digital veins

• Published in: Journal of applied physiology (1985) Vol. 109; no. 1; pp. 11 - 18
• Main Authors: ZERPA, H, BERHANE, Y, WOODCOCK, H, ELLIOTT, J, BAILEY, S. R
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Physiological Society 01.07.2010
• Subjects: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine - analogs & derivatives; 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine - pharmacology; Adrenergic alpha-2 Receptor Agonists; Adrenergic alpha-Agonists - pharmacology; Amides - pharmacology; Animals; Antioxidants - pharmacology; Benzophenanthridines - metabolism; Biological and medical sciences; Body Temperature Regulation - physiology; Brimonidine Tartrate; Cold Temperature; Cyclic N-Oxides - pharmacology; Cytoskeletal Proteins - metabolism; Cytoskeletal Proteins - physiology; Female; Fundamental and applied biological sciences. Psychology; Horses - metabolism; Horses - physiology; Kinases; Physiology; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - metabolism; Protein Kinase Inhibitors - pharmacology; Pyridines - pharmacology; Quinoxalines - pharmacology; Reactive Oxygen Species - analysis; Reactive Oxygen Species - metabolism; rho-Associated Kinases - metabolism; Rotenone - pharmacology; Spin Labels; Temperature effects; Vasoconstriction - physiology; Vasodilator Agents - pharmacology; Veins & arteries; Veins - drug effects; Veins - enzymology; Veins - physiology; α2-Adrenergic receptor; Reactive oxygen species; adrenoceptor; Cooling; Thermoregulation; Muscle contraction; α; Vertebrata; Mammalia; Blood vessel; Horse; Skin; Circulatory system; Perissodactyla; Vein; Ungulata
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01301.2009

A decrease in environmental temperature can directly affect the contractility of cutaneous vasculature, mediated in part by alpha(2)-adrenoceptors. Most of the cellular mechanisms underlying the cooling-enhanced contractility to alpha(2)-adrenoceptor agonists have been reported in cutaneous arteries but little information is available on cutaneous veins. To investigate the cellular mechanisms associated with the cooling-enhanced contraction to UK-14304 (alpha(2)-adrenoceptor agonist), isolated equine digital veins (EDVs) were studied at 30 degrees C and 22 degrees C. The effects of inhibitors were studied on the contractile response to UK-14304 (0.1 microM). The cooling-enhanced responses were inhibited by Rho kinase inhibitors [maximum response to UK-14304 95.2 +/- 8% of response to depolarizing Krebs solution (DKS) in control vessels cooled to 22 degrees C, compared with 31.4 +/- 6% in the presence of fasudil 1 microM and 75.8 +/- 6% with Y-27632 0.1 microM] and the effects of these inhibitors were considerably less at 30 degrees C (control response 56.4 +/- 5% of DKS; 34.9 +/- 6% with fasudil 1 microM and 50.6 +/- 9% with Y-27632 0.1 microM). Furthermore, Western blotting showed that one of the downstream targets for Rho kinase activity, ezrin/radixin/moesin, was phosphorylated after cooling and reduced by fasudil (1 microM) only at 22 degrees C. The activation of protein kinase C contributed to the contractile response, but predominantly at 30 degrees C (maximum response 82.3 +/- 9% of DKS for control; 57.7 +/- 10% in the presence of chelerythrine 10 microM) with no significant effect at 22 degrees C. The reduction of the response at 22 degrees C by antioxidants, rotenone (14% reduction), and tempol (21% reduction) suggested the contribution of reactive oxygen species (ROS). No evidence was obtained to support the participation of tyrosine kinase. These data demonstrate that Rho kinase activation and the production of ROS contributes to the cooling-enhanced contraction in these cutaneous digital veins.