Nitric oxide-mediated erectile effects of galantide but not galanin in vivo

Trinity J. Bivalacqua, Hunter C. Champion, Sunil K. Purohit, William A. Murphy, David H. Coy, Philip J. Kadowitz, Wayne J.G. Hellstrom

Research output: Contribution to journalArticle

Abstract

The purpose of this study was to investigate the in vivo effects of intracavernosal injections of galanin and galantide (a specific galanin receptor antagonist) on penile erection in the anesthetized cat. Erectile responses to galanin and galantide were compared with responses to a standard triple drug combination [1.65 mg papaverine, 25 μg phentolamine, and 0.5 μg prostaglandin E1 (PGE1)]. Intracavernosal injections of galanin (3-100 nmol) and galantide (0.1-3 nmol) induced penile erection in a dose-dependent manner. In terms of relative potency, galantide was approximately 100-fold more potent than galanin at increasing cavernosal pressure. The maximal increases in intracavernosal pressure in response to galanin and galantide were 83 and 95%, respectively, of the control triple drug combination. The total durations of erectile response caused by these peptides were significantly shorter (P < 0.05) than those by the triple drug combination. The nitric oxide synthase inhibitor L-NAME (20 mg) significantly decreased the erectile response in the cat to galantide but not to galanin, while the K(ATP)/+ channel antagonist U-37883A (3 mg) had no effect on the erectile response to galanin nor galantide. The results of the present study demonstrate that galantide, a putative antagonist for the galanin receptor, has more potent agonist activity than galanin in increasing intracavernosal pressure in the cat. Moreover, these data suggest that galantide, but not galanin, causes penile erection by an NO/cGMP-dependent mechanism. This is the first study to demonstrate that galanin may play a role in the physiology of penile erection. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)94-102
Number of pages9
JournalNitric Oxide - Biology and Chemistry
Volume4
Issue number2
DOIs
StatePublished - Apr 2000
Externally publishedYes

Keywords

  • Galanin
  • Galantide
  • K(ATP) channels
  • NO
  • Penile erection

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Clinical Biochemistry
  • Cancer Research

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  • Cite this

    Bivalacqua, T. J., Champion, H. C., Purohit, S. K., Murphy, W. A., Coy, D. H., Kadowitz, P. J., & Hellstrom, W. J. G. (2000). Nitric oxide-mediated erectile effects of galantide but not galanin in vivo. Nitric Oxide - Biology and Chemistry, 4(2), 94-102. https://doi.org/10.1006/niox.2000.0274