Faculty Collaboration Database

Acute nociceptive somatic stimulus sensitizes neurones in the spinal cord to colonic distension in the rat. J Physiol 2004 Oct 01;560(Pt 1):291-302

Date

07/31/2004

Pubmed ID

15284340

Pubmed Central ID

PMC1665216

DOI

10.1113/jphysiol.2004.069070

Scopus ID

2-s2.0-6444238582 (requires institutional sign-in at Scopus site)   39 Citations

Abstract

The common co-existence of fibromyalgia and chronic abdominal pain could be due to sensitization of spinal neurones (SNs), as a result of viscero-somatic convergence. The objective of this study is to explore the influence of acute nociceptive somatic stimulation in the form of acid injections, into the ipsilateral somatic receptive field of neurones responsive to colorectal distension (CRD), and the potential role of ionotropic glutamate receptors on sensitization. Action potentials of CRD-sensitive SNs were recorded extracellularly from the lumbar (L(2)-L(5)) spinal cord. Stimulus-response functions (SRFs) to graded CRD (10-80 mmHg, 30 s) were constructed before and 30 min after ipsilateral injection of low pH (4.0, 100 microl) saline into the somatic receptive fields. In some experiments, cervical (C(1)-C(2)) spinalization was performed to eliminate supraspinal influence. The selective NMDA receptor antagonist CGS 19755 and AMPA receptor antagonist NBQX were injected (25 micromol kg(-1), i.v.) to examine their influence on sensitization. Three types of neurones were characterized as short-latency abrupt (SLA, n = 24), short latency sustained (SLS, n = 12), and long-latency (LL, n = 6) to CRD. Ipsilateral injection of low pH (4.0) in the somatic receptive field, but not the contralateral gastrocnemius (GN) or front leg muscles, sensitized responses of these neurones to CRD. Spinalization had no influence on the development of low pH-induced sensitization. Both CGS 19755 and NBQX significantly attenuated the sensitized response to CRD in intact and spinalized animals. Acute nociceptive somatic stimulus sensitizes CRD-sensitive SNs receiving viscero-somatic convergence. The sensitization occurs at the spinal level and is independent of supraspinal influence. Ionotropic glutamate receptors in the spinal cord are involved in sensitization.

Author List

Peles S, Miranda A, Shaker R, Sengupta JN

Authors

Adrian Miranda MD Adjunct Professor in the Pediatrics department at Medical College of Wisconsin
Jyoti N. Sengupta PhD Professor in the Medicine department at Medical College of Wisconsin
Reza Shaker MD Assoc Provost, Sr Assoc Dean, Ctr Dir, Chief, Prof in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acids
Animals
Catheterization
Colon
Excitatory Amino Acid Antagonists
Lumbar Vertebrae
Male
Neurons, Afferent
Nociceptors
Pipecolic Acids
Quinoxalines
Rats
Rats, Sprague-Dawley
Receptors, AMPA
Receptors, N-Methyl-D-Aspartate
Spinal Cord
Spinal Cord Injuries
Stimulation, Chemical