Effect of prostaglandins D2, E2 and F2alpha on catecholamine release from slices of rat and rabbit brain.

Slices of rabbit or rat brain cortex were preincubated with [3H]noradrenaline, and slices of rabbit caudate nucleus or rat stratum with [3H]dopamine. The slices were then superfused and stimulated electrically. In rat cortex slices, PGE2 (0.01-1 millimicronmol/l) markedly reduced the stimulation-evoked overflow of tritium. PGF2alpha (1 millimicronmol/l) caused a slight decrease only after the formation of endogenous prostaglandins had been blocked by indomethacin. PGD2 (1 millimicronmol/l) had no effect. In slices of rabbit cortex and caudate nucleus as well as in rat striatal slices, none of the prostaglandins (1 millimicronmol/l) caused any change, irrespective of whether the production of endogenous prostaglandins was intact or blocked. The results show that, of three major prostaglandins that occur in the brain, only PGE2 is a potent presynaptic inhibitor of noradrenaline release in the rat. The catecholamine neurones of rabbit brain, and the dopamine neurones of rat striatum, are resistant to these prostaglandins.