In male Wistar rats PGF2alpha or PGE1 were injected intracerebroventricularly (icv) in a dose of 1 or 10 mug. Immediately or 1 hr after injection the locomotor and exploratory activity were measured. The levels of noradrenaline (NA), dopamine (DA) 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and acetylcholine (Ach) were measured in discrete brain areas. Both PGs applied ivc caused the depression of locomotor and exploratory activity in rats. PGE1 acted longer. Both substances but PGE1 more intensively affected the level of estimated biogenic amines in different brain structures. It is concluded that PGF2alpha and E1 are central nervous depressants. Both PGs affect neurons producing NA or 5-HT or Ach in discrete areas of brain in different manner. There is different susceptibility of brain structures on PGs action.