Response of femoral arteries to norepinephrine following endotoxicosis.
Relation between hypotension caused by endotoxin and the vascular response to norepinephrine was studied in rabbits following bolus injection of endotoxin (2 mg/kg). Seven rabbits were used as the nontreated, control animals (group I). Twelve endotoxin-shocked rabbits were divided into two groups from their hypotensive patterns: gradual hypotension group (group II, five animals) and immediate hypotension group (group III, seven animals). In group II, the mean arterial blood pressure decreased by less than 10% within 5 min after the administration of endotoxin, while the blood pressure immediately dropped over 40% in group III. No significant difference in blood pressure was observed between these two groups at 30, 60, and 240 min after the administration of endotoxin. Femoral arteries were resected from these animals 4 hr after the endotoxin treatment and were used to determine the vascular stiffness and contractile diameter response to 10(-5) M of norepinephrine. The diameter response was not significantly different at each pressure between 0 and 200 mm Hg between groups I and II or between groups I and III. However, the diameter response in the pressure range between 20 and 110 mm Hg was significantly higher in group III than in group II. The maximum diameter response was also significantly higher in group III than in group II. However, there was no significant difference in the wall stiffness between these two groups. These data show that the hypotensive response to endotoxin might be related to the vascular contractile response to norepinephrine.
Kato
T
T
Department of Biomedical Engineering, National Cardiovascular Center Research Institute, Osaka, Japan.
Hayashi
K
K
Takamizawa
K
K
D000818:Animals; D001794:Blood Pressure; D005263:Femoral Artery / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D011817:Rabbits; D012772:Shock, Septic / Q000503:physiopathology*; D014661:Vasoconstriction / Q000187:drug effects*
D009638:Norepinephrine