Intravesical resiniferatoxin desensitizes rat bladder sensory fibres without causing intense noxious excitation. A c-fos study

• Type: Article in International Scientific Journal
• Date: 1999

Authors

António Avelino Silva (Author) FMUP; Francisco Cruz (Author) FMUP; Coimbra, A (Author) Other

Journal

Title: European Journal of Pharmacology

Vol. 378

Pages: 17-22

ISSN: 0014-2999

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 37 Citations

Scopus - 42 Citations

Other information

Authenticus ID: P-001-3TF

DOI: 10.1016/s0014-2999(99)00451-3

Abstract (EN): In this study the desensitizing power of increasing concentrations of resiniferatoxin applied topically to the bladder mucosa, and the irritating properties of the most effective desensitizing dose, were determined with the aid of the spinal expression of the proto-oncogene c-fos. Desensitization was assessed by the decrease in the number of Fos-immunoreactive spinal neurons induced by the intravesical instillation of 1% acetic acid, when the latter was preceded by resiniferatoxin in concentrations between 1 and 1000 nM. Irritation, as shown by the noxious excitation of vesical sensory innervation, was measured by the c-fos response evoked by a single application of resiniferatoxin. As to the desensitizing power, resiniferatoxin produced a dose-dependent effect with a maximum at 100 nM, which decreased Fos-immunoreactive cell numbers to less than 10% of controls. No further decrease of c-fos activation occurred at 1000 nM. As to the irritating power, the saturation dose of resiniferatoxin (100 nM) produced a very weak c-fos activation in lumbosacral spinal cord segments. These data show that in an effective desensitizing concentration, resiniferatoxin is virtually devoid of nociceptive effects, in agreement with current clinical observations.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6