Dextro-phenylalanine inhibits potassium-evoked 3H-noradrenaline release from hypothalamus but not of 3H-dopamine from rat caudate nucleus.
Action of dextro-phenylalanine (d-Phe) on catecholamine release elicited by K+20 mM has been studied in isolated slices of rat central nervous system (CNS). d-Phe (3 x 10(-3)M) produced inhibition of the fractional release of 3H-noradrenaline but not of 3H-dopamine. The mentioned effect is Ca2+ dependent and was antagonized when this ion was incremented to 2.6 mM in the medium or in the presence of ionophore A-23187 (4 x 10(-5)M). Neither acetylsalicylic acid nor indomethacin (prostaglandin biosynthesis inhibitors) interferes with the effect of d-Phe, showing that by itself it would not reach through the prostaglandin pathway. d-Phe modified neither the noradrenaline neuronal uptake nor its metabolism at the CNS. The findings suggest that d-Phe acts through a Ca2+-dependent mechanism, possibly by specific receptors and in parallel with feedback circuits that involve alpha-adrenoceptors, muscarinic receptors, or prostaglandins.
D000818:Animals; D001241:Aspirin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002421:Caudate Nucleus / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D009778:Occipital Lobe / Q000378:metabolism; D010649:Phenylalanine / Q000494:pharmacology*; D011188:Potassium / Q000494:pharmacology; D011453:Prostaglandins / Q000502:physiology; D051381:Rats
D011453:Prostaglandins; D010649:Phenylalanine; D001241:Aspirin; D011188:Potassium; D002118:Calcium; D004298:Dopamine; D009638:Norepinephrine; D007213:Indomethacin