title: The effects of chronic losartan pretreatment on restraint stress-induced changes in motor activity, nociception and pentylenetetrazol generalized seizures in rats.
abstract: Accumulated evidence has shown that renin-angiotensin system has a pivotal role in stress responses.
  
  
  OBJECTIVE
  to assess the participation of AT1 receptor in stress-induced modulation of motor activity, nociception and seizure susceptibility in male Wistar rats.
  
  
  METHODS
  AT1 receptor antagonist losartan was administered subcutaneously to rats for 10 days at a dose of 10 mg/kg either alone or as a pretreatment before chronic restraint stress applied for 10 days. Locomotor and exploratory activity (open field test), the nociception (paw-pressure test) and the seizure susceptibility (pentylenetetrazol seizure test) were analysed.
  
  
  RESULTS
  Chronic restraint stress decreased motor activity and increased anxiety-like behaviour (grooming) while losartan pretreatment alleviated anxiety-like behaviour. Chronic restraint stress had an antinociceptive effect in paw-pressure test and losartan pretreatment abolished stress-induced antinociception. Both chronic restraint stress and losartan showed anticonvulsant activity in pentylenetetrazol seizure test. However, drug pretreatment attenuated this effect in chronically-stressed rats.
  
  
  CONCLUSIONS
  Our findings suggest that the AT1 receptor is involved in the mechanism of stress-induced changes in anxiety-like behaviour, nociception and seizure susceptibility in rats.
authors.affiliation: Institute of Neurobiology, Bulgarian Academy of Sciences, Medical University, Sofia, Bulgaria. pehlivanova@yahoo.com
authors.forename: Daniela M
authors.initials: DM
authors.lastname: Pechlivanova
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Stoynev
authors.forename: Jana D
authors.initials: JD
authors.lastname: Tchekalarova
mesh_terms: D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage*; D000818:Animals; D004195:Disease Models, Animal; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D019808:Losartan / Q000008:administration & dosage*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D010433:Pentylenetetrazole / Q000633:toxicity; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D012640:Seizures / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D019808:Losartan; D010433:Pentylenetetrazole