Depressed isoprenaline vascular response in endotoxic rats

The injection of a sublethal dose of E. coli endotoxin (0127 B8) to intact rats (2 mg/kg i.v) or adrenalectomized rats (0.01 mg/kg i.v.) depressed hypotensive responses to isoprenaline (0.2, 0.4, 0.8 microgram/kg i.v.) for at least 4 h following endotoxin injection. These findings evidence an early (under 1 h after administration) and long-lasting (over 4 h) depression of the vascular response to isoprenaline in endotoxic rats. This depression was not related to catecholamine adrenal discharge or to the hypotensive and lethal effects of endotoxin.