title: Subdiaphragmatic vagotomy increases the sensitivity of lumbar Aδ primary afferent neurons along with voltage-dependent potassium channels in rats.
abstract: Subdiaphragmatic vagal dysfunction causes chronic pain. To verify whether this chronic pain is accompanied by enhanced peripheral nociceptive sensitivity, we evaluated primary afferent neuronal excitability in subdiaphragmatic vagotomized (SDV) rats. SDV rats showed a decrease in the electrical stimuli-induced hind limb-flexion threshold at 250 Hz, but showed no similar effect at 5 or 2000 Hz, which indicated that lumbar primary afferent Aδ sensitivity was enhanced in SDV rats. The whole-cell patch-clamp technique also revealed the hyper-excitability of acutely dissociated medium-sized lumbar dorsal root ganglion (DRG) neurons isolated from SDV rats. The contribution of changes in voltage-dependent potassium (Kv) channels was assessed, and transient A-type K(+) (I(A) ) current density was apparently decreased. Moreover, Kv4.3 immunoreactivity in medium-sized DRG neurons was significantly reduced in SDV rats compared to sham. These results indicate that SDV causes hyper-excitability of lumbar primary Aδ afferent neurons, which may be induced along with suppressing I(A) currents via the decreased expression of Kv4.3. Thus, peripheral Aδ neuroplasticity may contribute to the chronic lower limb pain caused by SDV.
authors: Department of Toxicology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
authors: Sadayoshi
authors: S
authors: Furuta
authors: Lisa
authors: L
authors: Watanabe
authors: Seira
authors: S
authors: Doi
authors: Hiroshi
authors: H
authors: Horiuchi
authors: Kenjiro
authors: K
authors: Matsumoto
authors: Naoko
authors: N
authors: Kuzumaki
authors: Tsutomu
authors: T
authors: Suzuki
authors: Minoru
authors: M
authors: Narita
mesh_terms: D000818:Animals; D059350:Chronic Pain / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009619:Nociceptors / Q000502:physiology*; D024642:Potassium Channels, Voltage-Gated / Q000502:physiology*; D061251:Primary Cell Culture; D051381:Rats; D017207:Rats, Sprague-Dawley; D014628:Vagotomy / Q000009:adverse effects*; D020421:Vagus Nerve Diseases / Q000150:complications / Q000503:physiopathology*
chemical_list: D024642:Potassium Channels, Voltage-Gated