Uptake and release of [3H]GABA by growth cones isolated from neonatal rat brain.
A subcellular fraction highly enriched in neuronal growth cones was isolated from 5-day-old rat forebrain by a recently described method. The growth cone fraction was shown to have a sodium- and temperature-dependent, high-affinity (Km = 4.4 microM) uptake system for [3H]GABA. Electron microscopic autoradiography confirmed that this uptake was into growth cones since only these structures were heavily labelled with silver grains. High potassium induced the release of newly accumulated [3H]GABA from the growth cone fraction, about half of which was Ca2+-dependent. The presence of uptake and release systems for GABA in growth cones may simply reflect the development of growth cones into nerve terminals. Alternatively, these observations may indicate a role for neurotransmitter release in synaptogenesis.
D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D001921:Brain / Q000254:growth & development / Q000502:physiology*; D051381:Rats; D013569:Synapses / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D005680:gamma-Aminobutyric Acid