Effects of different bacterial endotoxins on the drinking behaviour of the rat.

Endotoxins of Pasteurella multocida, Pseudomonas aeruginosa, Neisseria gonorrhoeae, and Shigella sonnei, when given in a single intravenous injection in the rat, showed antidipsogenic effects on drinking behaviour stimulated by 48 h water deprivation, or by intracerebroventricular injection of carbachol (250 ng). In water deprived rats, the antidipsogenic effect was dose related. When drinking was induced by carbachol, endotoxins showed a very long-lasting inhibition. The effect was neither a consequence of behavioural alterations, nor due endotoxin peripheral vasodilatating properties.