title: Effective suppression of hippocampal seizures in rats by direct hippocampal cooling with a Peltier chip.
abstract: OBJECTIVE
  The use of focal brain cooling to eliminate epileptic discharges (EDs) has attracted increasing attention in the scientific community. In this study, the inhibitory effect of selective hippocampal cooling on experimental hippocampal seizures was investigated using a newly devised cooling system with a thermoelectric (Peltier) chip.
  
  
  METHODS
  A copper needle coated with silicone and attached to the Peltier chip was used for the cooling device. The experiments were performed first in a phantom model with thermography and second in adult male Sprague-Dawley rats in a state of halothane anesthesia. The cooling needle, a thermocouple, and a needle electrode for electroencephalography recording were inserted into the right hippocampus. Kainic acid (KA) was injected into the right hippocampus to provoke the EDs. The animals were divided into hippocampal cooling (10 rats) and noncooling (control, 10 rats) groups.
  
  
  RESULTS
  In the phantom study, the cooling effects (9 degrees C) occurred in the spherical areas around the needle tip. In the rats the temperature of the cooled hippocampus decreased below 20 degrees C within a 1.6-mm radius and below 25 degrees C within a 2.4-mm radius from the cooling center. The temperature at the needle tip decreased below 20 degrees C within 1 minute and was maintained at the same level until the end of the cooling process. The amplitude of the EDs was suppressed to 68.1 +/- 4.8% of the precooling value and remained low thereafter. No histological damage due to cooling was observed in the rat hippocampus.
  
  
  CONCLUSIONS
  Selective hippocampal cooling effectively suppresses the KA-induced hippocampal EDs. Direct hippocampal cooling with a permanently implantable system is potentially useful as a minimally invasive therapy for temporal lobe epilepsy and therefore could be an alternative to the temporal lobectomy.
authors: Department of Neurosurgery, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan.
authors: Nobuhiro
authors: N
authors: Tanaka
authors: Masami
authors: M
authors: Fujii
authors: Hirochika
authors: H
authors: Imoto
authors: Joji
authors: J
authors: Uchiyama
authors: Kimihiko
authors: K
authors: Nakano
authors: Sadahiro
authors: S
authors: Nomura
authors: Hirosuke
authors: H
authors: Fujisawa
authors: Ichiro
authors: I
authors: Kunitsugu
authors: Takashi
authors: T
authors: Saito
authors: Michiyasu
authors: M
authors: Suzuki
mesh_terms: D000818:Animals; D017679:Cryotherapy / Q000295:instrumentation* / Q000379:methods*; D004195:Disease Models, Animal; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D019060:Minimally Invasive Surgical Procedures; D051381:Rats; D017207:Rats, Sprague-Dawley; D012640:Seizures / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D013817:Thermography / Q000295:instrumentation / Q000379:methods