Inhibitory effect of GABAergic drugs in cocaine-induced genital reflexes in paradoxical sleep-deprived male rats

Pharmacol Biochem Behav. 2004 Jun;78(2):301-7. doi: 10.1016/j.pbb.2004.04.003.

Abstract

The aim of this study was to seek whether GABAergic drugs were involved in the action of cocaine on spontaneous genital reflexes (penile erection-PE, and ejaculation-EJ) of paradoxical sleep-deprived (PSD) male rats. After a 4-day period of PSD, each group was administered with GABAergic drugs 1 h prior to cocaine and placed in observation cages. The administration of gamma-aminobutyric acid (GABA)-A agonist (muscimol, 2 and 3 mg/kg sc) reduced the number of animals displaying PE, whereas all doses tested of muscimol and bicuculline significantly reduced the frequency of PE. Pretreatment with the lower doses of GABA-B antagonist, phaclofen (1 and 2 mg/kg sc), also significantly reduced the percentage of rats showing PE; however, after the higher dose injection, the proportion of animals with PE was similar to those seen after vehicle pretreatment. Both GABA-B agonist and antagonist significantly reduced the PE frequency for all doses used compared with the vehicle group. There were no significant differences between control and GABA-A drugs in EJ behavior, whereas phaclofen 2 mg/kg pretreatment increased the ejaculatory latency. These data show that GABAergic compounds inhibited PE in male PSD rats suggesting that this inhibition points to a differential role of GABA receptor subtypes.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cocaine / antagonists & inhibitors
  • Cocaine / pharmacology*
  • Dose-Response Relationship, Drug
  • Ejaculation / drug effects
  • Ejaculation / physiology
  • GABA Agents / pharmacology*
  • GABA-A Receptor Agonists
  • GABA-A Receptor Antagonists
  • Male
  • Neural Inhibition / drug effects*
  • Penile Erection / drug effects*
  • Penile Erection / physiology
  • Rats
  • Rats, Wistar
  • Receptors, GABA-A / physiology
  • Sleep Deprivation*

Substances

  • GABA Agents
  • GABA-A Receptor Agonists
  • GABA-A Receptor Antagonists
  • Receptors, GABA-A
  • Cocaine