Tetanus-induced asynchronous GABA release in cultured hippocampal neurons

• Published in: Brain research 2000-10, Vol.880 (1), p.198-201
• Main Authors: Jensen, Kimmo, Lambert, John D.C., Jensen, Morten Skovgaard
• Format: Article
• Language: English
• Subjects: 2-Amino-5-phosphonovalerate - pharmacology; 6-Cyano-7-nitroquinoxaline-2,3-dione - pharmacology; Action Potentials - physiology; Animals; Asynchronous release; Biological and medical sciences; Calcium - physiology; Cells, Cultured; Central nervous system; Cultured neurons; Egtazic Acid - analogs & derivatives; Egtazic Acid - pharmacology; Electric Stimulation; Electrophysiology; Evoked Potentials - drug effects; Evoked Potentials - physiology; Fundamental and applied biological sciences. Psychology; GABA; gamma-Aminobutyric Acid - metabolism; Hippocampus; Hippocampus - physiology; IPSC; Neurons - cytology; Neurons - drug effects; Neurons - physiology; Rats; Synapses - drug effects; Synapses - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/S0006-8993(00)02746-3

Asynchronous GABA release was studied in cultured hippocampal neurons using paired whole-cell recordings. Tetanization of the presynaptic GABAergic neuron was accompanied by a train of IPSCs which showed tetanic depression. Asynchronous IPSCs (asIPSCs) also developed during the train and continued for 1.85±0.3 s after the stimulation. The threshold frequency for evoking asIPSCs was 10 Hz, while maximal asynchronous activity was achieved at 40 Hz. Perfusion with EGTA-AM blocked asIPSCs. The elevation of [Ca 2+] i that accompanies presynaptic action potential firing triggers asynchronous release of GABA vesicles, thereby counteracting tetanic depression of synchronous IPSCs.