Effects of PK 8165, a partial benzodiazepine receptor agonist, on cholecystokinin-induced activation of hippocampal pyramidal neurons: a microiontophoretic study in the rat

Eur J Pharmacol. 1985 Jun 19;112(3):415-8. doi: 10.1016/0014-2999(85)90790-3.


Benzodiazepines (BZD) have been reported to suppress cholecystokinin-8S (CCK-8S)-induced activation. PK 8165, a ligand of BZD receptors, is an anxiolytic devoid of sedative and anticonvulsant effects. PK 8165, applied microiontophoretically or administered i.v. at low doses, suppressed CCK-8S-induced activation of hippocampal pyramidal neurons, whereas, at high doses it antagonized the effect of microiontophoretic applications of flurazepam. These results indicate that PK 8165 acts as a mixed agonist-antagonist at BZD receptors and suggest that the suppression of CCK-8S-induced activation by BZD might be related to their anxiolytic property rather than to their sedative or anticonvulsant activity.

MeSH terms

  • Animals
  • Anticonvulsants / pharmacology*
  • Benzodiazepinones / pharmacology
  • Cholecystokinin / pharmacology
  • Flumazenil
  • Flurazepam / pharmacology
  • Hippocampus / drug effects*
  • Injections, Intravenous
  • Iontophoresis
  • Male
  • Neurons / drug effects*
  • Pyramidal Tracts / drug effects*
  • Quinolines / pharmacology*
  • Rats
  • Rats, Inbred Strains
  • Receptors, GABA-A / drug effects*


  • Anticonvulsants
  • Benzodiazepinones
  • Quinolines
  • Receptors, GABA-A
  • Flumazenil
  • Cholecystokinin
  • Flurazepam
  • pipequaline