The effects of prostaglandins E2 and F2alpha on synaptosomal accumulation and release of 3H-norepinephrine.
Prostaglandins (PG) of both the E and F series may serve as modulators of norepinephrine (NE) release from peripheral sympathetic neurons. We have studied the effects of PGE2 and PGF2alpha on the accumulation and release of 3H-NE in the CNS using synaptosomes isolated from rat hypothalami. The release of 3H-NE from synaptosomes superfused with Krebs-Ringer bicarbonate buffer was multiphasic with an initial fast release phase followed by a slower release. Raising KCl concentration of the superfusion medium to 56mM during the slow release phase is known to stimulate 3H-NE release. PGE2 (1 X 10(-6)M) attenuated 3H-NE release during the fast phase and reduced the amount of 3H-NE released due to KCl stimulation. At lower concentrations of PGE2 there was no change in the release profile. PGF2alpha was without effect on 3H-NE release at all concentrations tested. The accumulation of 3H-NE was significantly diminished by PGE2 at a concentration of 1 X 10(-6)M, while a lower concentration (1 X 10(-7)M) was ineffective. PGF2alpha had no effect on 3H-NE accumulation at all concentrations investigated.
D000818:Animals; D002021:Buffers; D003470:Culture Media; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D011458:Prostaglandins E / Q000008:administration & dosage / Q000494:pharmacology*; D011460:Prostaglandins F / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D012636:Secretory Rate / Q000187:drug effects; D013574:Synaptosomes / Q000378:metabolism*
D002021:Buffers; D003470:Culture Media; D011458:Prostaglandins E; D011460:Prostaglandins F; D009638:Norepinephrine