PLASMA-CATECHOLAMINES IN THE CONSCIOUS RAT DURING ENDOTOXICOSIS

  • 1 January 1984
    • journal article
    • research article
    • Vol. 14  (3) , 189-201
Abstract
Blood pressure, heart rate and plasma catecholamines were determined in conscious unanesthetized rats given i.v. saline or endotoxin (LPS [lipopolysaccharide] from Salmonella enteritidis). Rats were monitored for 6 h and survival determined at 24 h. Blood pressure and heart rate measurements were determined using implanted arterial cannulae. The 1st of 2 protocols involved surgical implantation of cannulae 24 h prior to the administration of endotoxin (2.0 mg/kg) or saline. Significant hypotension during the 1st h following endotoxin was observed but significant increases in heart rate were not observed until 3 h. Plasma norepinephrine (NE) and epinephrine (E) were significantly elevated at 30 min. Norepinephrine remained elevated (6 times control) during 6 h, whereas E was elevated (60 times control) at 30 min but was less elevated at 6 h. The 2nd protocol involved endotoxin or saline administration immediately following implantation of cannulae. In this group, 16.7 mg/kg of endotoxin or saline was given. All animals died and plasma catecholamines were elevated at higher levels than those of the 1st group. Results suggest marked elevations in plasma catecholamines during endotoxicosis. Plasma NE and E may provide an early index of impending circulatory shock.