[Frontiers in Bioscience 14, 2203-2211, January 1, 2009]

Neuropeptides in tendinopathy

Alexander Scott1,2, Roald Bahr2,3

1Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, Canada, 2Centre for Hip Health, Vancouver Coastal Health Research Institute, Vancouver, Canada, 3Oslo Sport Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Normal Tendon Sensory Innervation
4. Normal Tendon Autonomic Innervation
5. Opiod System in Paratendon Nerves
6. Abnormal Innervation in Tendinopathy
7. Relationship of Neural Ingrowth and Pain
8. Essential Role of Neuropeptides in Tendon Healing
9. Stimulation of neuropeptide delivery by mechanical load and exercise
10. Convergent signaling by neuropeptides and nitric oxide
11. Production and response of neurotransmitters in tendon
12. Potential signaling pathways among nerves and tenocytes
13. Role of mast cells in tendinopathy
14. Potential role of neuropeptides in the response to paratendinous sclerosing injections
15. Conclusion and Perspectives
16. Acknowledgements
17. References

1. ABSTRACT

Overuse tendinopathy remains a major clinical burden for sports medicine and general practitioners. Recent studies have highlighted the role of sensory and autonomic nerves in generating or perpetuating the symptoms and tissue abnormalities associated with tendinopathy. We outline the neuroanatomy and potential roles of nerves and associated neuropeptides in tendinopathy. In addition, intriguing new data is reviewed which suggests that there may be a substantial intrinsic source of neuropeptides within tendons - namely, the tenocytes themselves. The potential roles of Substance P and mast cells are highlighted in particular. We discuss the implications for conservative management including sclerosing injections and exercise training.