Alterations in systemic and local colonic hemodynamic variables associated with intravenous infusion of ATP-MgCl2 in healthy anesthetized horses.
OBJECTIVE
To characterize alterations in systemic and local colonic hemodynamic variables associated with IV infusion of ATP-MgCl2 in healthy anesthetized horses.


METHODS
12 adult horses.


METHODS
Six horses were given ATP-MgCl2, IV, beginning at a rate of 0.1 mg of ATP/kg of body weight/min with incremental increases until a rate of 1.0 mg/kg/min was achieved. The remaining 6 horses were given an equivalent volume of saline (0.9% NaCl) solution over the same time period. Colonic and systemic hemodynamic variables and colonic plasma nitric oxide (NO) concentrations were determined before, during, and after infusion.


RESULTS
Infusion of ATP-MgCl2 caused a rate-dependent decrease in systemic and colonic vascular resistance, principally via its vasodilatory effects. A rate of 0.3 mg of ATP/kg/min caused a significant decrease in systemic and colonic arterial pressure and colonic vascular resistance without a significant corresponding decrease in colonic arterial blood flow. Consistent alterations in NO concentrations of plasma obtained from colonic vasculature were not detected, despite profound vasodilatation of the colonic arterial vasculature.


CONCLUSIONS
Results revealed that IV infusion of ATP-MgCl2 may be beneficial in maintaining colonic perfusion in horses with ischemia of the gastrointestinal tract, provided a sufficient pressure gradient exists to maintain blood flow.
Tetens
J
J
Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803-8410, USA.
Eades
S C
SC
Hosgood
G
G
Koch
C E
CE
Moore
R M
RM
D000255:Adenosine Triphosphate / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003106:Colon / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology; D004562:Electrocardiography / Q000187:drug effects / Q000662:veterinary; D005260:Female; D006736:Horses / Q000502:physiology*; D007262:Infusions, Intravenous; D016018:Least-Squares Analysis; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis / Q000097:blood; D011897:Random Allocation; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D009569:Nitric Oxide; D000255:Adenosine Triphosphate