title: Antidepressant-like activity of ellagic acid in unstressed and acute immobilization-induced stressed mice.
abstract: BACKGROUND
  The aim of present study was to evaluate antidepressant-like activity of ellagic acid in Swiss young male albino mice; and to explore the possible underlying mechanisms for this activity.
  
  
  METHODS
  Mice were immobilized for 150 min once only for induction of stress. Ellagic acid (8.75, 17.5, 35 mg/kg, po) and fluoxetine (20 mg/kg, ip) per se were administered to unstressed and stressed mice; and immobility periods were recorded using tail suspension test and forced swim test. The plasma nitrite levels were also estimated in unstressed and stressed mice. Effects of 7-nitroindazole (nNOS inhibitor), aminoguanidine (iNOS inhibitor), prazosin (α(1)-adrenoceptor antagonist), sulpiride (selective D(2)-receptor antagonist), and p-chlorophenylalanine (p-CPA - tryptophan hydroxylase inhibitor) on antidepressant-like activity of ellagic acid were also evaluated.
  
  
  RESULTS
  Ellagic acid (17.5 and 35 mg/kg, po) and fluoxetine per se significantly decreased immobility periods of unstressed and stressed mice, indicating significant antidepressant-like activity. There was no significant effect on locomotor activity of the mice. Ellagic acid significantly decreased the plasma nitrite levels in stressed mice only. Aminoguanidine significantly potentiated antidepressant-like activity and plasma nitrite decreasing effect of ellagic acid (35 mg/kg) in stressed mice. 7-Nitroindazole did not enhance antidepressant-like activity and plasma nitrite decreasing effect of ellagic acid in unstressed mice. Prazosin and p-CPA significantly attenuated antidepressant-like effect of ellagic acid (35 mg/kg) in unstressed mice only.
  
  
  CONCLUSIONS
  Thus, ellagic acid showed antidepressant-like activity in unstressed mice probably by interaction through adrenergic and serotonergic systems. On the other hand, antidepressant-like activity of ellagic acid in stressed mice might be through inhibition of inducible NOS.
authors.affiliation: Department of Pharmaceutical Sciences, Guru Jambheshwar University of Science and Technology, Haryana, India. din_dhingra@rediffmail.com
authors.forename: Dinesh
authors.initials: D
authors.lastname: Dhingra
authors.forename: Ritu
authors.initials: R
authors.lastname: Chhillar
mesh_terms: D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D004610:Ellagic Acid / Q000494:pharmacology*; D004644:Emotions / Q000187:drug effects*; D010134:Fenclonine / Q000494:pharmacology; D005473:Fluoxetine / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D019417:Hindlimb Suspension / Q000379:methods; D007103:Immobilization / Q000009:adverse effects / Q000379:methods; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects; D009573:Nitrites / Q000097:blood; D011224:Prazosin / Q000494:pharmacology; D012149:Restraint, Physical / Q000009:adverse effects / Q000379:methods; D013315:Stress, Psychological / Q000097:blood* / Q000188:drug therapy*; D013469:Sulpiride / Q000494:pharmacology; D013550:Swimming
chemical_list: D000928:Antidepressive Agents; D006146:Guanidines; D007191:Indazoles; D009573:Nitrites; D005473:Fluoxetine; D004610:Ellagic Acid; D013469:Sulpiride; D010134:Fenclonine; C004479:pimagedine; C080122:7-nitroindazole; D011224:Prazosin