DOCA-salt treatment enhances responses to endothelin-1 in murine corpus cavernosum

Can J Physiol Pharmacol. 2008 Jun;86(6):320-8. doi: 10.1139/Y08-031.

Abstract

The penis is kept in the flaccid state mainly via a tonic activity of norepinephrine and endothelins (ETs). ET-1 is important in salt-sensitive forms of hypertension. We hypothesized that cavernosal responses to ET-1 are enhanced in deoxycorticosterone acetate (DOCA)-salt mice and that blockade of ETA receptors prevents abnormal responses of the corpus cavernosum in DOCA-salt hypertension. Male C57BL/6 mice were unilaterally nephrectomized and treated for 5 weeks with both DOCA and water containing 1% NaCl and 0.2% KCl. Control mice were uninephrectomized and received tap water with no added salt. Animals received either the ETA antagonist atrasentan (5 mg x day(-1) x kg(-1) body weight) or vehicle. DOCA-salt mice displayed increased systolic blood pressure (SBP), and treatment with atrasentan decreased SBP in DOCA-salt mice. Contractile responses in cavernosal strips from DOCA-salt mice were enhanced by ET-1, phenylephrine, and electrical field stimulation (EFS) of adrenergic nerves, whereas relaxations were not altered by IRL-1620 (an ETB agonist), acetylcholine, sodium nitroprusside, and EFS of nonadrenergic noncholinergic nerves. PD59089 (an ERK1/2 inhibitor), but not Y-27632 (a Rho-kinase inhibitor), abolished enhanced contractions to ET-1 in cavernosum from DOCA-salt mice. Treatment of DOCA-salt mice with atrasentan did not normalize cavernosal responses. In summary, DOCA-salt treatment in mice enhances cavernosal reactivity to contractile, but not to relaxant, stimuli, via ET-1/ETA receptor-independent mechanisms.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Atrasentan
  • Desoxycorticosterone / administration & dosage*
  • Endothelin A Receptor Antagonists
  • Endothelin-1 / administration & dosage*
  • Endothelin-1 / antagonists & inhibitors
  • Endothelin-1 / genetics
  • Hypertension / etiology
  • Hypertension / physiopathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Muscle, Smooth / drug effects
  • Muscle, Smooth / physiology
  • Penile Erection / drug effects
  • Penile Erection / physiology
  • Penis / blood supply*
  • Penis / drug effects*
  • Penis / physiology
  • Pyrrolidines / administration & dosage
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sodium Chloride / administration & dosage*
  • Vasodilation / drug effects
  • Vasodilation / physiology

Substances

  • Endothelin A Receptor Antagonists
  • Endothelin-1
  • Pyrrolidines
  • RNA, Messenger
  • Desoxycorticosterone
  • Sodium Chloride
  • Atrasentan