title: Calcium-activated release of nitric oxide potentiates excitatory synaptic potentials in immature rat sympathetic preganglionic neurons.
abstract: 1. Whole cell patch recordings were made from sympathetic preganglionic neurons (SPNs), the majority of which contain brain nitric oxide synthase (bNOS), in transverse spinal cord slices of 12- to 16-day-old rats. 2. Repetitive discharge of SPNs induced by a train of depolarizing current pulses (40 Hz. 10 s) was followed by a long-lasting increase (140 +/- 22%, mean +/- SD) of the amplitude of excitatory postsynaptic potentials (EPSPs) evoked by stimulation of lateral funiculus in 50 of 75 SPNs. 3. In slices pretreated with the nitric oxide synthase inhibitors, NG-monomethyl-L-arginine (L-NMA: 100 microM) or Nw-nitro-L-arginine (L-NARG; 30 microM) or with bovine hemoglobin (100 microM), repetitive discharge of SPNs was not followed by a significant increase of EPSPs. 4. Superfusing the slices with L-arginine (L-Arg, 300 microM) but not D-Arg reversibly increased the EPSPs by an average of 140 +/- 19%. 5. Inclusion of the Ca2+ chelator 1.2-bis(2-aminophenoxy)- ethane-N,N,N',N'-tetraacetic acid (BAPTA, 1 mM) in the patch electrodes resulted in no significant increase of EPSPs after repetitive discharge in all cells studied. 6. It is concluded that during repetitive discharge of SPNs, Ca2+ influx via voltage-gated channels activates bNOS, resulting in a release of nitric oxide and potentiation of EPSPs.
authors: Department of Anatomy and Neurobiology, Medical College of Ohio, Toledo 43614, USA.
authors: S Y
authors: SY
authors: Wu
authors: N J
authors: NJ
authors: Dun
mesh_terms: D000320:Adrenergic Fibers / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001339:Autonomic Fibers, Preganglionic / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006454:Hemoglobins / Q000494:pharmacology; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D016202:N-Methylaspartate / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*
chemical_list: D015220:Calcium Channels; D002614:Chelating Agents; D004791:Enzyme Inhibitors; D006454:Hemoglobins; D019335:Nitroarginine; D009569:Nitric Oxide; D004533:Egtazic Acid; D016202:N-Methylaspartate; D001120:Arginine; D019001:Nitric Oxide Synthase; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium