Journal of Neurophysiology, Vol 74, Issue 3 981-989, Copyright © 1995 by APS

ARTICLES

Fiber types contributing to dorsal root reflexes induced by joint inflammation in cats and monkeys

K. A. Sluka, H. Rees, K. N. Westlund and W. D. Willis
Department of Anatomy and Neurosciences, University of Texas Medical Branch, Galveston 77555-0843, USA.

1. Injection of kaolin and carrageenan into the knee joint of cats or monkeys resulted in an acute inflammation. Four hours after injection of the knee joint, efferent activity could be evoked in articular afferent fibers and in dorsal root filaments. We interpret this efferent activity to be dorsal root reflexes (DRRs). Under our experimental conditions, the DRRs were generally synchronized compound action potentials, although in some cases single-unit activity was also observed. 2. DRRs were not produced in animals with uninflamed knee joints and normal body temperatures. 3. Recordings from two different sites on cut dorsal root filaments ipsilateral to the inflamed knee joint allowed the determination of the conduction velocities of groups of afferent fibers carrying DRRs. The DRRs occurred in A beta-, A delta-, and C fibers. However, in these experiments the peripheral destination of the afferent fibers was unknown. 4. To prove that DRRs occurred in joint afferents, recordings were made from two different sites on the proximal stump of the medial articular nerve that innervated the inflamed knee. The DRRs were again found in all fiber types, i.e., group II, III, and IV (A beta, A delta, and C) articular afferent fibers. 5. Compound DRRs were recorded from the central end of a cut dorsal root filament after electrical stimulation at C fiber intensity of a dorsal root adjacent to the filament. This DRR activity was eliminated by extensive dorsal rhizotomies of the L2-S1 roots.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				J. Wang, Y. Ren, X. Zou, L. Fang, W. D. Willis, and Q. Lin Sympathetic Influence on Capsaicin-Evoked Enhancement of Dorsal Root Reflexes in Rats J Neurophysiol, October 1, 2004; 92(4): 2017 - 2026. [Abstract] [Full Text] [PDF]

				Q. Lin, X. Zou, L. Fang, and W. D. Willis Sympathetic Modulation of Acute Cutaneous Flare Induced by Intradermal Injection of Capsaicin in Anesthetized Rats J Neurophysiol, February 1, 2003; 89(2): 853 - 861. [Abstract] [Full Text] [PDF]

				Y. B. Peng, J. Wu, W. D. Willis, and D. R. Kenshalo GABAA and 5-HT3 Receptors Are Involved in Dorsal Root Reflexes: Possible Role in Periaqueductal Gray Descending Inhibition J Neurophysiol, July 1, 2001; 86(1): 49 - 58. [Abstract] [Full Text] [PDF]

				Q. Lin, X. Zou, and W. D. Willis Adelta and C Primary Afferents Convey Dorsal Root Reflexes After Intradermal Injection of Capsaicin in Rats J Neurophysiol, November 1, 2000; 84(5): 2695 - 2698. [Abstract] [Full Text] [PDF]

				Q. Lin, J. Wu, and W. D. Willis Dorsal Root Reflexes and Cutaneous Neurogenic Inflammation After Intradermal Injection of Capsaicin in Rats J Neurophysiol, November 1, 1999; 82(5): 2602 - 2611. [Abstract] [Full Text] [PDF]