Effects of propofol and thiopental on the central nervous system during nociceptive stimulation in cats.
OBJECTIVE
Nociceptive stimulation may increase central nervous system (CNS) activity during anesthesia. However, it is not known whether propofol and thiopental have a similar inhibitory effect on the CNS during nociceptive stimulation. Therefore, we compared the antinociceptive effects of propofol and thiopental in cats.


METHODS
In 12 cats, anesthesia was induced with 4% halothane in oxygen and maintained with 0.5% halothane in oxygen. The cortical electroencephalogram (EEG) and the electrical activity from the midbrain reticular neurons (R-MUA) were measured before and after sciatic nerve stimulation. The cats were then allocated to receive cumulative doses of either propofol (n = 6) or thiopental (n = 6) i.v. at 5-min intervals. Two minutes after each dose, the cortical EEG and the R-MUA were compared before and after sciatic nerve stimulation.


RESULTS
Propofol and thiopental depressed the basal R-MUA to a similar degree at each dose. Sciatic nerve stimulation increased the R-MUA, and there were no differences in the maximum R-MUA values between propofol and thiopental. The cortical EEGs after each dose of anesthetic without stimulation showed similar patterns, and the patterns of change with stimulation were also similar for these two anesthetics.


CONCLUSIONS
Propofol and thiopental have similar antinociceptive effects in cats.
Inada
T
T
Department of Anesthesiology, Kansai Medical University, 10-15 Fumizono-cho, Moriguchi, Osaka 570-8507, Japan.
Murao
K
K
Shingu
K
K
Yamada
K
K
Nakao
S
S
Nagata
A
A