Electron microscopic demonstration of neurons and synaptic terminals selectively accumulating (3H)GABA in goldfish optic tectum.

After injection of (3H)GABA in the goldfish tectum, several neural structures selectively accumulating the labeled neurotransmitter were revealed by electron microscopic autoradiography. A number of labeled neurons was observed in the periventricular layer, while some scattered neurons were present in more superficial layers. Different types of axon terminals were also labeled in the stratum marginale, stratum fibrosum and griseum superficiale and stratum griseum centrale. Labeled dendrites, in particular those belonging to the periventricular neurons, were also noted.