Influence of polyphloretin phosphate on the central effects of prostaglandin E2 and F2α in rats

The possibility that polyphloretin phosphate (PPP) antagonizes the central effects elicited by prostaglandin (PG) E₂ and F_2a was investigated. PPP was administered i.c.v. to male Wistar rats (10 or 25 µg) 10 or 30 min before i.c.v. injection of PGE₂ or PGF_2a (1 or 10 µg). The duration of several components of behavior, the degree of irritability, and the rectal temperature of rats were measured; the levels of noradrenaline, dopamine, 5-hydroxytryptamine, and 5-hydroxyindoleacetic acid were measured spectrophotofluorometrically in discrete brain areas. PPP antagonized temperature and behavioral changes induced in rats by PGF_2a, but not those induced by PGE₂. The magnitude of antagonism depended on the dose of PPP and on the time of the pretreatment before PGF_2a administration. Changes in the level of biogenic amines in discrete brain areas evoked by PGs were not affected by PPP.