Mt. Herrero et al., EFFECT OF VARIOUS DEPOLARIZING AGENTS ON ENDOGENOUS AMINO-ACID NEUROTRANSMITTER RELEASE IN RAT CORTICAL-NEURONS IN CULTURE, Neurochemistry international, 32(3), 1998, pp. 257-264
The purpose of this study is to determine whether differences in membr
ane potential and/or intracellular Ca2+ increments are implicated in a
programmed release of amino acid neurotransmitters (aspartate, glutam
ate, glycine and GABA) in cortical neurons in culture. According to ou
r results, it is possible to assume that difference in membrane potent
ial is not the only signal which starts the amino acid neurotransmitte
r release, but there are other necessary conditions at the start of th
is amino acid release. One of these conditions could be the increment
in intracellular Ca2+, but our results indicate that, in cortical neur
ons in culture, the total intracellular Ca2+ increments are not import
ant on release levels, but are the stimulating agent which produces th
is intracellular Ca2+ increment. From these results we may infer: (1)
that in rat cortical neurons there are neurons which contain and relea
se glutamate, aspartate, glycine and GABA, (2) that in cortical neuron
s the 36.6+/-5.8% of the neurons are GABA-ergic, (3) that the membrane
potential and the total intracellular calcium are not only responsibl
e for the release of these amino acids but also the depolarizing agent
which plays an important role in this release, and (4) that glutamate
and aspartate and glutamate and GABA are localized in different vesic
ular pools or in different cell neurons. (C) 1998 Elsevier Science Ltd
. All rights reserved.