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Advances in Orthopedics
Volume 2012, Article ID 361534, 6 pages
http://dx.doi.org/10.1155/2012/361534
Research Article

Hyaluronan Does Not Affect Bupivacaine’s Inhibitory Action on Voltage-Gated Potassium Channel Activities in Bovine Articular Chondrocytes

1Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, LA 70112, USA
2Department of Orthopaedic Surgery and Tulane Institute of Sports Medicine, Tulane University School of Medicine, New Orleans, LA, USA
3Tulane Cancer Center, Louisiana Cancer Research Consortium, Tulane Center for Aging, Tulane Center for Stem Cell Research and Regenerative Medicine, Tulane University School of Medicine, New Orleans, LA 70112, USA

Received 21 January 2012; Accepted 24 February 2012

Academic Editor: Masato Takao

Copyright © 2012 William Hester et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objectives. The objective of this paper is to determine if hyaluronan affects bupivacaine’s anesthetic function. Methods. Whole cell patch clamp recordings were performed on bovine articular chondrocytes cultured in 60 mm dishes. The chondrocytes were treated with phosphate-buffered saline (control group), 7.5 mg/mL hyaluronan (Orthovisc), 0.25% bupivacaine, or a mixture of 7.5 mg/mL hyaluronan and 0.25% bupivacaine. Outward currents were elicited by step depolarization from −90 mV to 150 mV with 5 mV increments and holding for 200 ms. Results. The amplitude of outward currents elicited at 150 mV was 607.1±135.4 pA (mean ± standard error) in the chondrocytes treated with phosphate buffered saline, 550.0±194.9 pA in the chondrocytes treated with hyaluronan, 18.4±8.3 pA in the chondrocytes treated with bupivacaine, and 12.8±2.6 pA in the chondrocytes treated with a mixture of hyaluronan and bupivacaine. Conclusion. Hyaluronan does not affect bupivacaine’s inhibitory action on the potassium channel activities in bovine articular chondrocytes. This finding suggests that intra-articular injection of a mixture of hyaluronan and bupivacaine may not affect the anesthetic effects of bupivacaine.