title: Protective effects of gastrodia elata on aluminium-chloride-induced learning impairments and alterations of amino acid neurotransmitter release in adult rats.
abstract: OBJECTIVE
  High brain levels of aluminum (Al) can be neurotoxic and cause learning and memory deficits. Gastrodia elata (GE) is a Chinese herb widely used for improving mental function in traditional Chinese medicine. We measured changes in Al-induced neurotransmitter alteration and performance on a learning and memory task to elucidate the mechanism of Al toxicity and to assess whether these alterations could be attenuated by GE.
  
  
  METHODS
  Thirty-six adult, male rats were randomly divided into six groups. Four Al-exposed groups were given aluminum chloride at 5 mg/kg/day or 10 mg/kg/day (i.p.) for two months, with two of these groups (one for each dose of Al) receiving GE (0.4 g/kg, via oral intubation, with the GE powder mixed in the drinking water) while the other two groups received vehicle. A GE control group was given injections of saline plus GE and a saline control group was given injections of saline and with 3 injection days and one day off. A step-down test was used to measure learning and memory ability. Al concentrations in the neocortex were assayed with a graphite furnace atomic absorption spectrophotometer. Amino acid neurotransmitter levels in the neocortex were determined by high performance liquid chromatogram-fluorescence.
  
  
  RESULTS
  Al-exposed rats showed impaired learning and memory ability as indicated by shorter step down latency and more retention errors. Cortical concentrations (mean +/- SEM) of Al were: 56.22 +/- 34.10 ng/g (wet weight) in the Saline control group; 172.87 +/- 111.06 in the 5 mg/kg/dayAl group; 289.15 +/- 102.55 in the 10 mg Al group; 74.98 +/- 19.00 in the GE control group; 232.55 +/- 35.74 in 5 mg Al+GE group; and 291.35 98.38 in 10 mg Al+GE group respectively. Al exposure produced a significant increase in cortical GABA levels. Gastrodia elata reduced learning and memory deficits without affecting brain Al levels.
  
  
  CONCLUSIONS
  Rats exposed to AlCl_{3} suffer from deficits in learning and memory, accompanied by increases in GABA levels in the neocortex. Gastrodia elata is effective in improving memory functions and normalizing GABA levels.
authors.affiliation: Department of Psychology, Peking University, Beijing, China.
authors.forename: He
authors.initials: H
authors.lastname: Shuchang
authors.forename: Niu
authors.initials: N
authors.lastname: Qiao
authors.forename: Niu
authors.initials: N
authors.lastname: Piye
authors.forename: He
authors.initials: H
authors.lastname: Mingwei
authors.forename: Sun
authors.initials: S
authors.lastname: Xiaoshu
authors.forename: Shao
authors.initials: S
authors.lastname: Feng
authors.forename: Wang
authors.initials: W
authors.lastname: Sheng
authors.forename: Mark
authors.initials: M
authors.lastname: Opler
mesh_terms: D000077410:Aluminum Chloride; D017607:Aluminum Compounds; D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D002712:Chlorides; D002853:Chromatography, Liquid / Q000379:methods; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D031668:Gastrodia / Q000737:chemistry*; D007859:Learning Disabilities / Q000139:chemically induced / Q000378:metabolism / Q000517:prevention & control; D008297:Male; D019579:Neocortex / Q000187:drug effects / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism*; D008517:Phytotherapy / Q000379:methods*; D028321:Plant Preparations / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects
chemical_list: D017607:Aluminum Compounds; D002712:Chlorides; D018377:Neurotransmitter Agents; D028321:Plant Preparations; D000077410:Aluminum Chloride