title: Paraplegia prevention by oral pretreatment with memantine in a rabbit model.
abstract: OBJECTIVE
  To evaluate the role of memantine (N-methyl-d-aspartate receptor antagonist) pretreatment for the prevention of spinal cord ischemia after infrarenal aortic clamping in a rabbit model.
  
  
  METHODS
  Thirty New Zealand White rabbits were divided into 5 different groups of 6 rabbits. Groups 60-7 and 60-5 received oral memantine 60 mg once a day for 7 and 5 days, respectively, and groups 30-5 and 30-3 received oral memantine 30 mg once a day for 5 and 3 days, respectively, all before surgery. Group C (control) received normal feeds without memantine. A paraplegic model was created by clamping both the aorta and the inferior vena cava infrarenally and just proximal to their bifurcations for 45 minutes. The modified Tarlov score, motor evoked potential (MEP), serum memantine concentration, and histopathology of the spinal cord were evaluated.
  
  
  RESULTS
  The mean modified Tarlov scores were 4.2±1.3, 4.3±1.0, 4.2±1.3, 4.3±1.2, and 0.8±1.6 in groups 60-7, 60-5, 30-5, 30-3, and C, respectively at 6, 24, 48, and 72 hours (P<.009 for individual groups vs control). Percentage amplitude loss of MEP by the end of surgery was 29.5%±46.3%, 11.9%±28.0%, 30.0%±46.8%, 16.7%±40.8%, and 81.8%±40.3% for the 5 groups, respectively (P=.049). After declamping, MEP reappeared in 83%, 100%, 83%, 83%, and 33% of cases in the 5 groups, respectively (P=.073). The serum memantine level was similar in the 4 memantine groups. Spinal cords were normal in most of the rabbits in groups 60-7, 60-5, 30-5, and 30-3, but severely ischemic in most of the rabbits in group C (P=.041).
  
  
  CONCLUSIONS
  Oral memantine pretreatment is protective against spinal cord ischemia, and can be an additional strategy for the prevention of paraplegia during thoracoabdominal aortic surgeries.
authors.affiliation: Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Nirmal
authors.initials: N
authors.lastname: Panthee
authors.affiliation: Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan. Electronic address: ono-tho@h.u-tokyo.ac.jp.
authors.forename: Minoru
authors.initials: M
authors.lastname: Ono
authors.affiliation: Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Morota
authors.affiliation: Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Tsuruhito
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Itoda
authors.affiliation: Department of Neuropathology, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Ikemura
authors.affiliation: Department of Pharmacy, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Takehito
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Pharmacy, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Saito
authors.affiliation: Department of Cardiac Surgery, University of Tokyo, Hongo Bunkyo-ku, Tokyo, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Motomura
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001012:Aorta, Abdominal; D003250:Constriction; D019054:Evoked Potentials, Motor; D008559:Memantine / Q000008:administration & dosage* / Q000494:pharmacology; D010264:Paraplegia / Q000473:pathology / Q000517:prevention & control*; D011817:Rabbits; D020760:Spinal Cord Ischemia / Q000473:pathology / Q000517:prevention & control*
chemical_list: D008559:Memantine