title: Lateralized hippocampal effects of vasoactive intestinal peptide on learning and memory in rats in a model of depression.
abstract: BACKGROUND
  Findings of pharmacological studies revealed that vasoactive intestinal peptide (VIP) plays a modulatory role in learning and memory. A role of the peptide in the neurobiological mechanisms of affective disorders was also suggested.
  
  
  OBJECTIVE
  The objectives are to study the involvement of VIP in learning and memory processes after unilateral and bilateral local application into hippocampal CA1 area in rats with a model of depression (bilateral olfactory bulbectomy--OBX) and to test whether VIP receptors could affect cognition.
  
  
  RESULTS
  VIP (50 ng) and combination (VIP(6-28) 10 ng + VIP 50 ng) microinjected bilaterally or into the right CA1 area improved the learning and memory of OBX rats in shuttle-box and step-through behavioral tests as compared to the saline-treated OBX controls. Left-side VIP microinjections did not affect the number of avoidances (shuttle box) and learning criteria (step through) as compared to the left-side saline-treated OBX controls. The administration of the combination into left CA1 influenced positively the performance in the step-through task. VIP antagonist (VIP(6-28), 10 ng) did not affect learning and memory of OBX rats. These findings suggest asymmetric effect of VIP on cognitive processes in hippocampus of rats with OBX model of depression.
  
  
  CONCLUSIONS
  Our results point to a lateralized modulatory effect of VIP injected in the hippocampal CA1 area on the avoidance deficits in OBX rats. The right CA1 area was predominantly involved in the positive effect of VIP on learning and memory. A possible role of the PAC1 receptors is suggested.
authors.affiliation: Department of Physiology and Pathophysiology, Medical University Varna, 55 Marin Drinov St., 9000, Varna, Bulgaria. mvelikova@yahoo.com
authors.forename: Margarita
authors.initials: M
authors.lastname: Ivanova
authors.forename: Stiliana
authors.initials: S
authors.lastname: Belcheva
authors.forename: Iren
authors.initials: I
authors.lastname: Belcheva
authors.forename: Negrin
authors.initials: N
authors.lastname: Negrev
authors.forename: Roman
authors.initials: R
authors.lastname: Tashev
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D003071:Cognition / Q000187:drug effects; D003863:Depression / Q000503:physiopathology*; D004195:Disease Models, Animal; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D007858:Learning / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018005:Receptors, Vasoactive Intestinal Peptide / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D018696:Neuroprotective Agents; D010446:Peptide Fragments; D018005:Receptors, Vasoactive Intestinal Peptide; C113198:vasoactive intestinal peptide (6-28); D014660:Vasoactive Intestinal Peptide