Activation of gamma-aminobutyric acid(A) receptors in the paraventricular nucleus of the hypothalamus reduces apomorphine-, N-methyl-D-aspartic acid- and oxytocin-induced penile erection and yawning in male rats

Neurosci Lett. 2000 Mar 10;281(2-3):127-30. doi: 10.1016/s0304-3940(00)00821-1.

Abstract

The effect of muscimol and baclofen injected into the paraventricular nucleus of the hypothalamus on penile erection and yawning induced by apomorphine, oxytocin and N-methyl-D-aspartic acid (NMDA) was studied in male rats. Muscimol (20-200 ng), but not baclofen (200 ng), injected into the paraventricular nucleus of the hypothalamus 10 min before apomorphine (50 ng), oxytocin (10 ng) or NMDA (50 ng) reduced penile erection and yawning induced by the above compounds given into the paraventricular nucleus. Bicuculline (250 ng) injected into the paraventricular nucleus 5 min before muscimol (100 ng) prevented the inhibitory effect of muscimol on penile erection and yawning induced by apomorphine, oxytocin and NMDA. The present results show that gamma-aminobutyric acid (GABA) inhibits penile erection and yawning by acting on GABA(A) receptors in the paraventricular nucleus of the hypothalamus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apomorphine / pharmacology*
  • Baclofen / pharmacology
  • Dopamine Agonists / pharmacology
  • Excitatory Amino Acid Agonists / pharmacology
  • GABA Agonists / pharmacology
  • GABA-A Receptor Agonists*
  • GABA-B Receptor Agonists
  • Male
  • Muscimol / pharmacology
  • N-Methylaspartate / pharmacology*
  • Oxytocin / pharmacology*
  • Paraventricular Hypothalamic Nucleus / drug effects*
  • Paraventricular Hypothalamic Nucleus / metabolism
  • Penile Erection / drug effects*
  • Penile Erection / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Yawning / drug effects*
  • Yawning / physiology

Substances

  • Dopamine Agonists
  • Excitatory Amino Acid Agonists
  • GABA Agonists
  • GABA-A Receptor Agonists
  • GABA-B Receptor Agonists
  • Muscimol
  • Oxytocin
  • N-Methylaspartate
  • Baclofen
  • Apomorphine