Sialorphin (the mature peptide product of Vcsa1) relaxes corporal smooth muscle tissue and increases erectile function in the ageing rat

Kelvin P. Davies, Moses Tar, Catherine Rougeot, Arnold Melman

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

OBJECTIVE: To determine if the mature peptide product of the Vcsa1 gene, sialorphin, could restore erectile function in ageing rats, and whether these effects are mediated through relaxation of corporal smooth muscle tissue, as we recently reported that Vcsa1 is one of the most down-regulated genes in the corpora of rats in three distinct models of erectile dysfunction, and gene transfer of plasmids expressing Vcsa1 into the corpora of ageing rats restored erectile function. MATERIALS AND METHODS: Sialorphin was injected intracorporeally into retired breeder rats, and the effect on the physiology of corporal tissue was analysed by intracorporal/blood pressure (ICP/BP) measurement at different times after injection. In organ-bath studies, the ability of sialorphin (1 μg/mL) to enhance C-type natriuretic peptide (CNP) relaxation of corporal smooth muscle tissue strips was investigated after pre-contraction with 1 μm phenylephrine. RESULTS: Intracorporal injection of 100 μg sialorphin into retired breeder rats resulted in a time-dependent increase in the ICP/BP response to electrostimulation of the cavernosal nerve. After 55-65 min the ICP/BP ratio increased to =0.6, a value associated with normal erectile function. In organ-bath studies after pre-contraction with 1 μm phenylephrine, 1 μm CNP significantly (67%) increased the relaxation rate of corporal tissue. This rate of relaxation was increased by 2.5-fold after incubation with sialorphin (1 μg/mL) compared with carrier alone. CONCLUSION: These results show that sialorphin has a role in erectile function, probably through a mechanism that involves relaxation of corporal smooth muscle tissue.

Original languageEnglish (US)
Pages (from-to)431-435
Number of pages5
JournalBJU International
Volume99
Issue number2
DOIs
StatePublished - Feb 2007

Keywords

  • Ageing
  • Erectile dysfunction
  • Sialorphin
  • Vcsa1

ASJC Scopus subject areas

  • Urology

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