[Effect of pyramidal tract stimulation on segmental spinal cord potentials].
The author reports his results of the effect of pyramidal tract stimulation on the segmental spinal cord potentials (seg-SCP) using a total of 50 Wistar rats. Forty two Wistar rats were used to observe the effects of a pyramidal tract stimulation on the seg-SCP evoked by hindpaw stimulation. Another 5 Wistar rats were used to observe dorsal column stimulation as the conditioning stimuli instead of pyramidal tract stimulation. And the other 3 Wistar rats were used for both pyramidal tract and dorsal column stimulation as a separate trial. The seg-SCP of the rats consisted of three major peaks, P1, N1 and P2. P2 was separated into a first (P2F) and second component (P2S). The P2F peak was constantly preceded by a small notch, considered to be the onset of P2F, and named the P2F initial peak. The P2F peak amplitude of the seg-SCP was significantly decreased by pyramidal tract stimulation, while the P2F initial peak amplitude remained unchanged. This effect persisted until the concentration of sevoflurane was reduced to below 1.5% or until the peak arterial blood pressure was decreased to below 80 mmHg. The amplitude of both the P2F initial peak and the P2F peak were decreased significantly by dorsal column stimulation. These findings indicated that inhibition of the P2F peak amplitude was a characteristic effect of the pyramidal tract stimulation on the seg-SCP, while inhibition of the overall P2F amplitude was characteristic of the dorsal column stimulation.
Urushibara
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Department of Orthopaedic Surgery, Jikei University School of Medicine, Tokyo.
D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials; D008297:Male; D011712:Pyramidal Tracts / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000502:physiology*