title: Involvement of arginine-vasopressin in the diuretic and hypotensive effects of Pereskia grandifolia Haw. (Cactaceae).
abstract: BACKGROUND
  Pereskia grandifolia Haw. (Cactaceae), popularly known as "ora-pro-nobis" is well recognized in Brazilian traditional medicine as a diuretic agent, although no scientific data have been published to support this effect. The aim of this work is to evaluate the diuretic and hypotensive activities of the infusion (INFPG) and the ethanol extract (HEPG) of Pereskia grandifolia and possible mechanism of action.
  
  
  METHODS
  The infusions (2.5-10%) and the HEPG (3-100 mg/kg) were orally administered in a single dose or daily (for seven days) to rats. The urine excretion rate, pH, density, conductivity and content of Na(+), K(+), Cl(-) and HCO(3)(-) were measured in the urine of saline-loaded animals. In collected serum samples the concentration of electrolytes, urea, creatinine, aldosterone, vasopressin and angiotensin converting enzyme (ACE) activity were evaluated. The involvement of V(2) vasopressin receptor in the diuretic activity and the hypotensive effect of HEPG were also determined.
  
  
  RESULTS
  Water excretion rate was significantly increased by HEPG, while the urinary K(+) and Cl(-) excretion was significantly reduced in acute and prolonged treatment. The oral administration of the HEPG (30mg/kg) significantly reduced serum levels of vasopressin and the mean arterial pressure (MAP) in normotensive rats. All other evaluated parameters have not been affected by any treatment.
  
  
  CONCLUSIONS
  The results showed that HEPG could present compound(s) responsible for aquaretic activities with no signs of toxicity, and this effect could involve a reduction in the arginine-vasopressin release.
authors.affiliation: Instituto de Ciências Exatas, Agrárias, Tecnológicas e Geociências, Universidade Paranaense, Umuarama, PR, Brazil.
authors.forename: Caroline Calixto
authors.initials: CC
authors.lastname: Kazama
authors.forename: Denise Thiemi
authors.initials: DT
authors.lastname: Uchida
authors.forename: Karina Natally
authors.initials: KN
authors.lastname: Canzi
authors.forename: Priscila
authors.initials: P
authors.lastname: de Souza
authors.forename: Sandra
authors.initials: S
authors.lastname: Crestani
authors.forename: Arquimedes
authors.initials: A
authors.lastname: Gasparotto
authors.forename: Antonio
authors.initials: A
authors.lastname: Laverde
mesh_terms: D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D029421:Cactaceae; D002712:Chlorides / Q000097:blood; D004232:Diuretics / Q000494:pharmacology*; D005260:Female; D007022:Hypotension / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves; D011188:Potassium / Q000097:blood; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002712:Chlorides; D004232:Diuretics; D010936:Plant Extracts; D001127:Arginine Vasopressin; D011188:Potassium