ABSTRACT
Neurons were free-hand isolated under the stereomicroscope from the bovine trigeminal mesencephalic nucleus. These neurons were challenged with monoclonal antibodies against the alpha1 and the beta2/3 subunits of the GABA(A) receptor. The neurons showed a strong reaction to both antibodies. The reaction was mainly intracellular in the round cell bodies and in the axoplasm of the axon emerging from these pseudounipolar cells. This suggests the synthesis of these subunits in the cell body and their transport along the axon.
Subject(s)
Mesencephalon/physiology , Neurons, Afferent/physiology , Receptors, GABA-A/metabolism , Animals , Axonal Transport , Cattle , Protein Subunits/metabolism , Subcellular Fractions/metabolismABSTRACT
1. Studies about the permeation of labelled chloride and GABA across single plasma membranes microdissected from vestibular Deiters' neurons have yielded two unexpected results: (a) intracellular GABA stimulates chloride permeation in an asymmetric fashion (efflux being favoured); (b) under certain conditions GABA permeates by a diffusion mechanism in the out-->in direction across these plasma membranes. 2. These two main results have been obtained over many years together with a host of other indications about the fine mechanism of these events. Thus, a picture has emerged of their physiological meaning within the context of the functioning of the GABAA synapses between the Purkinje cells and the Deiters' neurons. 3. In short, it is proposed that at these synapses GABA accumulates into the postsynaptic neuron after its release and activation of the postsynaptic receptors. GABA accumulated in the Deiters' neurons is involved in the process of chloride extrusion to build an inward directed electrochemical gradient for chloride.
