title: Effects of risperidone on learning and memory in naive and MK-801-treated rats.
abstract: OBJECTIVE
  The aim of this study was to investigate the effects of an atypical antipsychotic risperidone (RIS; 0.06, 0.125 or 0.25 mg/kg, intraperitoneal, i.p.) on learning and memory processes, both in naive and MK-801-treated (0.15 mg/kg, i.p.) rats.
  
  
  METHODS
  Modified elevated plus maze (mEPM), passive avoidance (PA) and Morris water maze (MWM) tasks were used.
  
  
  RESULTS
  In the mEPM test, RIS (0.125 or 0.25 mg/kg) significantly decreased the transfer latency and reversed MK-801-induced prolongation in the transfer latency of rats on the 2nd day. In the PA test, RIS (0.125 or 0.25 mg/kg) slightly decreased step-through latency (retention latency) but this finding did not reach statistical significance in naive rats. RIS had no effect on MK-801-induced reduction of retention latency. In the MWM test, RIS (0.06, 0.125 or 0.25 mg/kg, i.p.) neither affected the time spent in the escape platform quadrant, nor the distance to the platform in naive rats. It (0.125 mg/kg) tended to increase MK-801-induced reduction of time spent in the escape platform quadrant, but this finding was insignificant. RIS (0.125 mg/kg) significantly shortened MK-801-induced elongation in the distance to the platform. RIS had no effect on the swimming speed of the animals.
  
  
  CONCLUSIONS
  RIS might be effective in treating cognitive dysfunctions associated with schizophrenia.
authors: Psychopharmacology Laboratory, Department of Pharmacology, Faculty of Medicine, Kocaeli University, Umuttepe, Turkey. ikomsu@hotmail.com
authors: Ipek Komsuoglu
authors: IK
authors: Celikyurt
authors: Furuzan Yildiz
authors: FY
authors: Akar
authors: Guner
authors: G
authors: Ulak
authors: Oguz
authors: O
authors: Mutlu
authors: Faruk
authors: F
authors: Erden
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects; D016291:Dizocilpine Maleate / Q000009:adverse effects*; D007858:Learning / Q000187:drug effects*; D007859:Learning Disabilities / Q000139:chemically induced / Q000517:prevention & control; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced / Q000517:prevention & control; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D018967:Risperidone / Q000494:pharmacology*
chemical_list: D014150:Antipsychotic Agents; D016291:Dizocilpine Maleate; D018967:Risperidone