Two pools of amines in synaptic vesicles of rat pineal nerves.

Two pools of amines (noradrenaline and serotonin) are characterized by histochemistry and electrical stimulation in the synaptic vesicles from rat pineal nerves : a loosely bound pool located in the matrix and a tightly bound pool located in the core. A similar distribution is adopted by the false transmitter formed by the administration of 5-hydroxydopamine. The behaviour of both pools under electrical stimulation and in resting conditions is compatible with the idea that the amines stored in the core form a reserve pool and the amines stored in the matrix correspond to a functional pool, which can be released spontaneously and by electrical stimulation, being replaced by the transmitter newly synthesized or by the amines stored in the core. (A presentation of these results was made at the III International Symposium on Nervous Transmission, Helsinki, Finland, 1979).