O R I G I N A L A R T I C L E Immunocytes modulate ganglionic nitric oxide release which later affects their activity level

Pedal ganglia excised and maintained in culture for up to 2 h, release NO at low levels. The range can vary between 0 to 1.1 nM. Non-stimulated immunocytes do not significantly stimulate ganglionic NO release when incubated with pedal ganglia. However, ganglia exposed to immunocytes that had been previously activated by a 30 min incubation with interleukein1β, release NO significantly above basal levels. In these experiments, 91 ± 2.5% of the non-stimulated immunocytes exhibited form factors in the 0.72 to 0.89 range (sampled prior to ganglionic addition), whereas 62 ± 10.3% of the interleukin 1β stimulated immunocytes had form factors in the 0.39 to 0.49 range, demonstrating activation. Addition of the nitric oxide synthase inhibitor, L-NAME (10–4 M), inhibited basal ganglionic NO release as well as that initiated by exposing the ganglia to activated immunocytes. Interestingly, non activated immunocytes, following ganglionic exposure, exhibited activity levels in the 13% range, representing a non significant increase. Cells exposed to interleukin 1 β had a 65% activity level at the beginning of the experiment, followed by a drop of activity to 19 ± 3.2% after ganglionic exposure. Repeating this last observation in the presence of L-NAME (10–4 M), brought the activity level of the immunocytes back to the pre-ganglionic exposure level of activity, demonstrating that ganglionic NO was involved in down regulating immunocyte activity.