Abstract
Propofol is known as one of the short acting (i.v.) anesthetics. However, detail mechanism of the anesthetic effect of propofol is still unknown. It is very important to know which areas of CNS are activated by the propofol administration for clarifying the neuronal mechanism of its anesthetic effect. We introduced sodium pentobarbital (Nembutal) as a positive control drug. Three stages of anesthetic levels were defined as light, middle and deep anesthetic stages from the frequency of the wave forms of the EEG activity during intravenous infusion of propofol or Nembutal. The large spikes were exposed on the small waves at the middle stage during propofol (9.95mg/kg/20min.) or Nembutal (43.2mg/kg/66min.) infusion. When the anesthetic level is in deep, almost no clear waves were recorded during propofol (32.75mg/kg/32min.) or Nembutal (59.7mg/kg/68min.) infusion. A large number of Fos protein-LI cells was expressed in the medullary dorsal horn, area postrema, parabrachial nucleus, inferior colliculus, PAG, lateral hypothalamus and basolateral Amygdara after noxious heat stimulation of the face during middle or deep stage after propofol or Nembutal treatment. The strong depression of Fos protein-LI cells in the all areas of CNS was observed at deep stage after Nembutal treatment. On the other hand, no clear change in Fos expression was observed at the deep stage during propofol treatment. These date suggest that the propofol may induce anesthetic effect without any action on the pain pathway in CNS. [Jpn J Physiol 54 Suppl:S173 (2004)]
