Current Perspectives on the Therapeutic Utility of VR1 Antagonists

K.   J.   Valenzano; Q.      Sun

Abstract

This review gives a brief overview of the expression patterns, molecular pharmacology and physiological roles of the vanilloid receptor 1 (VR1). Particular emphasis is given to the therapeutic utility of VR1 modulators. Small molecule agonists of VR1, including capsaicin and RTX, are currently utilized for a number of clinical syndromes, including intractable neuropathic pain, spinal detrusor hyperreflexia, and bladder hypersensitivity; however, antagonists of VR1 have yet to reach the clinic. While the classic VR1 antagonist, capsazepine has proven a useful tool for unraveling the molecular pharmacology of VR1, in vivo studies with this compound have had limited success due to poor pharmacokinetic properties and species selectivity issues. With the cloning of VR1 in 1997, the pharmaceutical community has been provided a molecular target for high throughput screening and small molecule lead discovery and optimization. As a result, resurgence in the interest of VR1 antagonists has given way to many new pharmacological agents that may provide better tools to probe VR1 physiology, and ultimately yield promising therapeutic agents.

Keywords: vr1, capsaicin, resiniferatoxin, antagonist, hyperalgesia, pain, capsazepine, inflammation