Cholinergic nerve terminals contain ascorbic acid which induces Ca2+-dependent release of acetylcholine and ATP from isolated Torpedo synaptic vesicles.

We have shown that a soluble, low-molecular weight, alkali-labile and oxidation-sensitive factor, prepared from the electric organ of Torpedo ocellata, induces Cap-dependent acetylcholine (ACh) release from isolated Torpedo synaptic vesicles [ 1,2]. Diverse activities of ascorbic acid in the brain have been reported [3-81. These include effects on metabolism of biogenic amines [9] and on release of neurotransmitters from isolated mammalian vesicles [lo]. We therefore tested the possibility that ascorbic acid may be the soluble factor present in Torpedo and thus a naturally-occurring mediator of ACh release in vivo.