Serotonin-antagonist Effects of 1-(1-naphthyl)piperazine on Operant Behavior of Squirrel Monkeys

Neuropharmacology. 1989 Aug;28(8):817-21. doi: 10.1016/0028-3908(89)90173-1.


1-(1-Naphthyl)piperazine (1-NP) has been reported to have serotonin antagonist properties at the 5-HT2 subtype of receptor, and it has been suggested that it may have agonist actions at the 5-HT1 site. In the present experiments, the effects of 1-NP alone and in combination with a variety of 5-HT agonists, were studied in squirrel monkeys performing under a number of reinforcement schedules. The phenalkylamine hallucinogen 4-bromo-2,5-dimethoxyamphetamine (DOB, 0.01-0.3 mg/kg), which is thought to have predominant actions at 5-HT2 sites, reduced responding under fixed-interval (FI) schedules of presentation of food, and these decreases were blocked by 1-NP (0.3-1.0 mg/kg) or by the selective 5-HT2 antagonist, ketanserin (0.3 mg/kg). 1-(1-Naphthyl)piperazine also antagonized the decreases in responding produced by quipazine (0.1-5.6 mg/kg), another agonist with predominant 5-HT2 actions. 1-(m-Chlorophenyl)piperazine (mCPP, 0.1-3.0 mg/kg) and 1-(m-trifluoromethylphenyl)piperazine (TFMPP, 0.1-3.0 mg/kg), both thought to act primarily at 5-HT1 sites, also decreased responding and this effect was blocked by methysergide and by 1-NP, but not by ketanserin. The effects of 1-NP (0.3-5.6 mg/kg) given alone were not like those of mCPP or TFMPP. 1-(1-Naphthyl)piperazine produced moderate increases in responding under shock-avoidance schedules, whereas only decreases in responding were seen after mCPP and TFMPP.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 2,5-Dimethoxy-4-Methylamphetamine / analogs & derivatives
  • 2,5-Dimethoxy-4-Methylamphetamine / pharmacology
  • Animals
  • Conditioning, Operant / drug effects*
  • Electroshock
  • Female
  • Food
  • Male
  • Piperazines / pharmacology*
  • Quipazine / pharmacology
  • Reinforcement Schedule
  • Saimiri
  • Serotonin Antagonists / pharmacology*


  • Piperazines
  • Serotonin Antagonists
  • 2,5-Dimethoxy-4-Methylamphetamine
  • 1-(3-trifluoromethylphenyl)piperazine
  • 2,5-dimethoxy-4-bromoamphetamine
  • Quipazine
  • 1-(1-naphthyl)piperazine
  • 1-(3-chlorophenyl)piperazine