Central and peripheral adrenergic mechanisms in endotoxin fever and newborn guinea pigs.

In 0--3 day-old guinea pigs cerebroventricular pretreatment with alpha-methyl-p-tyrosine failed to modify the course of fever induced by E. coli endotoxin administration into the cerebral ventricles. Central or intraperitoneal administration of phentolamine or central administration of propranolol were also ineffective. Intraperitoneal propranolol, however, prevented both the first and the second temperature rise after endotoxin, while the transient fall in temperature that usually occurs between them still ensued. Central noradrenergic mechanisms seem to play, at most, a minor role in the mediation of endotoxin fever, while the integrity of peripheral beta adrenergic receptors is indispensable for the febrile response to occur.