Role of Pertussis Toxin-Sensitive G-proteins in Synaptic Transmission and Plasticity at Corticostriatal Synapses. Ka-Choi Tang,1 and David M. Lovinger1,2. Department of 1Molecular Physiology and Biophysics, 2Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615.
APStracts 6:0480N, 1999.
The roles pertussis toxin-sensitive (PTX) G-proteins in corticostriatal synaptic transmission and long-term synaptic depression (LTD) were examined using extracellular field potential and whole-cell voltage-clamp recordings in striatal slices. High frequency stimulation (HFS) produced LTD, defined as long-lasting decreases in both synaptically-driven population spikes (PSs) measured with field potential recording, and excitatory postsynaptic currents (EPSCs) measured with whole-cell recording. Striatal LTD could not be induced in slices obtained from rats that had received a unilateral intrastriatal injection of PTX. However, LTD could be induced in slices obtained from paired control slices. Furthermore, striatal LTD was prevented by pretreatment with N-ethylmaleimide (NEM), another compound that disrupts the function of PTX-sensitive G-proteins. NEM, itself, also potentiated PS and EPSC amplitudes. In addition, NEM increased the frequency and amplitude of both spontaneous and miniature EPSCs and decreased paired-pulse facilitation ratio, suggesting that it might act upon both pre- and post-synaptic sites. Our findings suggest that PTX-sensitive G-proteins have multiple roles at corticostriatal synapses, including regulation of synaptic transmission at both pre- and postsynaptic sites, and a key role in striatal LTD.
Received 12 July 1999; accepted in final form 15 September 1999.
APS Manuscript Number J569-9.
Article publication pending Journal of Neurophysiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 21 December 1999