PROSTAGLANDIN-E1 INHIBITS ACUTE CELL DEHYDRATION THIRST

I.p. injected PG[prostaglandin]E1 (100 .mu.g/kg) inhibits specifically the drinking induced in rats by both i.p. and i.v. 2 M NaCl (6 ml/kg) and compound 48/80 [p-methoxy-phenethyl methylamine formaldehyde product] (100 .mu.g/kg, i.p.). Probenecid (150 mg/kg, i.p.), which is not a dipsogen, has no effect on the PGE1 induced inhibition of acute cell dehydration thirst. Apparently, PGE1 acts upon the peripheral mast cells, inhibiting their secretion and thus affecting the H2O intake associated with the activation of these cells either by hypertonicity or specific stimulants of amine release. These results raise the possibility that endogenous PG might be involved in the modulation of some of the signals which convey to the brain information on the tonicity of the body fluids.