Tyrosine's vasoactive effect in the dog shock model depends on the animal's starting blood pressure.
We examined the effect of tyrosine (10-200 mg/kg given intravenously) or placebo on blood pressure (BP) in dogs made hypotensive (systolic BP = 50 mm Hg) by bleeding one hour previously. Animals which, prior to induction of hypotension, had been normotensive (mean arterial pressures, [MAP] less than or equal to 145 mm Hg) subsequently exhibited a dose-related increase in BP after tyrosine administration. In contrast, dogs which had been hypertensive prior to bleeding exhibited a fall in BP after tyrosine. These observations indicated that prior cardiovascular status may be an important factor influencing responses to exogenous tyrosine, and to endogenous catecholamines produced from the tyrosine.
D000818:Animals; D001794:Blood Pressure; D004195:Disease Models, Animal; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D007022:Hypotension / Q000188:drug therapy*; D014443:Tyrosine / Q000627:therapeutic use*
D014443:Tyrosine