Influence of polyphloretin phosphate on the central effects of prostaglandin E2 and F2alpha in rats.

The possibility that polyphloretin phosphate (PPP) antagonizes the central effects elicited by prostaglandin (PG) E2 and F2alpha was investigated. PPP was administered i.c.v. to male Wistar rats (10 or 25 microgram) 10 or 30 min before i.c.v. injection of PGF2 or PGF2alpha (1 or 10 microgram). The duration of several component 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 spectrophoto-fluorometrically in discrete brain areas. PPP antagonized temperature and behaviroal changes induced in rats by PGF2alpha, but not those induced by PGE2. The magnitude of antagonism depended on the dose of PPP and on the time of the pretreatment before PGF2alpha administration. Changes in the level of biogenic amines in discrete brain areas evoked by PGs were not affected by PPP. We found that PPP antagonizes the central effects of PGF2alpha but not those of PGE2, and that changes of biogenic amines in discrete brain areas elicited by PGs are not specific.