The Journal of Neuroscience, January 15, 2003, 23(2):367-372
BRIEF COMMUNICATION
Persistent Changes in Spontaneous Firing of Purkinje Neurons
Triggered by the Nitric Oxide Signaling Cascade
Spencer L.
Smith and
Thomas S.
Otis
Department of Neurobiology and Brain Research Institute, University
of California at Los Angeles School of Medicine, Los Angeles,
California 90095
Many types of neurons fire spontaneously because of the
activity of pacemaking ion channels. Although endogenous firing can serve as a persistent signal to downstream targets, little attention has been paid to factors that might modulate such intrinsic electrical activity. We tested for modulation of spontaneous firing of Purkinje neurons in cerebellar slices under conditions in which principal synaptic inputs were blocked. Loose-patch recordings from single neurons show that sustained (>40 min) increases in the spontaneous firing rate can be triggered by activation of the nitric oxide-cGMP signaling pathway. Inhibitors of soluble guanylate cyclase and protein
kinase G block this modulation. Increases in firing rate are also
observed after stimulation of parallel fibers but not in response to
basket cell activity. These findings elucidate a novel role for the
nitric oxide-cGMP signaling cascade in the brain. This mechanism could
permit long-term adjustments in the baseline firing rate of
endogenously active neurons in response to changes in afferent activity.
Key words:
intrinsic; protein kinase G; cGMP; cerebellum; nitric oxide synthase; pacemaking
Copyright © 2003 Society for Neuroscience 0270-6474/03/232367-06$05.00/0