GABA-induced conductance fluctuations in cultured spinal neurones

Abstract

ANALYSIS of conductance fluctuations induced by putative neurotransmitters has provided a new level of resolution of the molecular events underlying postsynaptic membrane responses^1–3. So far, conductance fluctuation (or ‘noise’) analysis has been applied to neuromuscular synapses in vertebrates and invertebrates^1–6 and has not yet been applied at synapses in the mammalian central nervous system (CNS), largely because of the inherent complexity and relative inaccessibility of the CNS. Recently, methods for growing dissociated neurones derived from fetal mouse spinal cord in cell culture have become sufficiently established⁷ to allow long-term stable intracellular recording. Using this preparation we have applied fluctuation analysis to the membrane current flow induced by the putative inhibitory amino acid transmitter γ-aminobutyric acid (GABA) and report here an initial estimate of the conductance and duration of ion channels activated by GABA.