title: Effects of morphine on stress induced anxiety in rats: role of nitric oxide and Hsp70.
abstract: The present study evaluated the effects of morphine on acute and chronic restraint stress (RS) induced anxiety modulation and the possible involvement of nitric oxide (NO) and heat shock proteins (Hsp70) during such effects. Acute RS (×1) induced anxiogenesis in the elevated plus maze (EPM) test which was associated with lowered brain NO metabolites (NOx) and elevated Hsp70 levels. Pretreatment with morphine (1 and 5 mg/kg) and L-arginine (500 mg/kg) attenuated the RS effects on EPM activity and brain NOx, whereas, Hsp70 levels were further augmented. Co-administration of both agents showed synergistic effects. By contrast, repeated RS (×15) did not induce any significant changes in EPM activity or brain NOx, but brain Hsp70 levels stayed elevated. Administration of morphine or L-arginine prior to chronic RS did not influence such chronic stress induced changes in behavioral and biochemical markers, but appreciably attenuated chronic RS induced elevation in Hsp70 levels. These results suggest that acute and chronic RS induced anxiety modulations were differentially influenced by morphine and L-arginine and that complex interactions involving brain NO and unregulated Hsp70 could regulate such effects.
authors.affiliation: Department of Pharmacology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 110007, India.
authors.forename: Jagdish C
authors.initials: JC
authors.lastname: Joshi
authors.affiliation: Department of Pharmacology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 110007, India.
authors.forename: Arunabha
authors.initials: A
authors.lastname: Ray
authors.affiliation: Department of Pharmacology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 110007, India. Electronic address: kavgul2002@yahoo.com.
authors.forename: Kavita
authors.initials: K
authors.lastname: Gulati
mesh_terms: D000208:Acute Disease; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000188:drug therapy* / Q000503:physiopathology; D001120:Arginine / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000503:physiopathology; D002908:Chronic Disease; D004195:Disease Models, Animal; D004357:Drug Synergism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D017208:Rats, Wistar; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000188:drug therapy / Q000503:physiopathology
chemical_list: D014151:Anti-Anxiety Agents; D018840:HSP70 Heat-Shock Proteins; D009569:Nitric Oxide; D009020:Morphine; D001120:Arginine
keywords: Hsp70; Morphine; Nitric oxide; Stress; l-Arginine