Long-term transformation of an inhibitory into an excitatory GABAergic synaptic response.
For a constant membrane potential, a predominantly inhibitory GABAergic synaptic response is shown to undergo long-term transformation into an excitatory response after pairing of exogenous gamma-aminobutyric acid (GABA) with postsynaptic depolarization or pairing of pre- and postsynaptic stimulation. Current- and voltage-clamp experiments suggest that this synaptic transformation is due to a shift from a net increase of conductance to a net decrease of conductance in response to GABA. GABA-induced elevation of intracellular calcium is prolonged after the same stimulus pairing and may, therefore, contribute to this synaptic transformation via Ca(2+)-activated phosphorylation pathways. This synaptic transformation, which does not follow unpaired stimulus presentations, occurs in a neuronal compartment spatially separated from the soma, which also changes during stimulus pairing.
Alkon
D L
DL
Neural Systems Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
Sánchez-Andrés
J V
JV
Ito
E
E
Oka
K
K
Yoshioka
T
T
Collin
C
C
D000818:Animals; D002118:Calcium / Q000502:physiology; D003214:Conditioning, Classical / Q000502:physiology*; D004553:Electric Conductivity; D066298:In Vitro Techniques; D015640:Ion Channel Gating; D008564:Membrane Potentials; D009433:Neural Inhibition; D010786:Photoreceptor Cells / Q000502:physiology*; D015290:Second Messenger Systems; D012908:Snails; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D005680:gamma-Aminobutyric Acid; D002118:Calcium