[Abstract Title]. - Society for Neuroscience

understood. The cytokine GRO/KC (growth-related oncogene; CXCL1) shows strong, rapid
upregulation in dorsal root ganglion (DRG) in both nerve injury and inflammatory pain models.
We examined the direct effects of GRO/KC on small diameter DRG neurons, which are
predominantly nociceptive. Whole cell voltage clamp technique was used to measure voltageactivated
K currents in acutely cultured adult rat small diameter sensory neurons. Fluorescently
labeled isolectin B4 (IB4) was used to classify cells as IB4-positive or IB4-negative. In IB4negative
neurons, voltage-activated K current densities of both transient and sustained
components were increased 1.6 fold after overnight incubation with GRO/KC (1.5 nM), without
changes in voltage dependence or kinetics. The average values for the slow and fast decay time
constants at 20 mV were unchanged by GRO/KC. The amplitudes of the fast inactivating
component and the steady-state component were increased significantly with no shift in the
voltage dependence of inactivation. These effects on K currents were completely blocked by coincubation
with protein synthesis inhibitor cycloheximide (CHX) or NF-kB inhibitor pyrrolidine
dithiocarbamate (PDTC). In contrast, the voltage-activated K current of IB4-positive neurons
was unchanged by GRO/KC. Results suggest that GRO/KC has important effects in
inflammatory process via its direct actions on sensory neurons, and activation of NF-kB is
involved in its enhancement of K currents.
Disclosures: R. Yang, None; J.A. Strong, None; J. Zhang, None.
Poster
268. Neuropathic Pain Mechanisms: Ion Channels
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 268.17/GG14
Topic: D.08.l. Neuropathic pain: Mechanisms
Support: McMaster University
Title: Increased excitability of dorsal root ganglion sensory neurones in an animal model of
neuropathic pain
Authors: Y. ZHU, Q. WU, *J. L. HENRY;
Inst. for Pain Rese & Care, McMaster Univ., Hamilton, ON, Canada
Abstract: Supportive evidence exists that pain following peripheral nerve injury is maintained
by ectopic activity in primary sensory neurons, which is thought to arise from the dorsal root
ganglion (DRG) somata, the axons and peripheral nerve terminals. Studies aimed at investigating
the role of primary afferents in neuropathic pain (NeP) models have so far focused on small
diameter neurones despite evidence of hyperexcitability of spinal neurones in response to both