Prostaglandin E1 Prostaglandin E2 and Endotoxin Failure to Produce Fever in the Japanese Freshwater Snail Semisulcospira libertina

Abstract

The thermopreferendum (preferred temperature) of the Japanese freshwater snail (Semisulcospira libertina) was determined in an aquatic temperature gradient after injection of prostaglandin E1 prostaglandin E2 and LPS. Injected doses of each pyrogen ranged from a toxic dose to less than l/20th of the toxic dose. Toxic effect of the highest doses of pyrogen disappeared within 120 min. No fever occurred during the 150 min observation following the pyrogen injection. The present results support the hypothesis that fever was selected as a way of defending against infection only after the period of the emergence of the molliiscus, i.e., the early Cambrian period. © 1988, PHYSIOLOGICAL SOCIETY OF JAPAN. All rights reserved.