Dopaminergic Inhibition of Dorsal Horn Cell Activity in the Cat

• 영문명: Dopaminergic Inhibition of Dorsal Horn Cell Activity in the Cat
• 발행기관: 대한생리학회-대한약리학회
• 저자명: Kyung Chul Kim Hong Kee Shin Kee Soon Kim
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제2권 제6호, 661~670쪽, 전체 10쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1998.01.01

영문 초록

Dopamine has been generally known to exert antinociceptive action in behavioral pain test, such as tail flick and hot plate test, but there appears to be a great variance in the reports on the antinociceptive effect of dopamine depending on the dosage and route of drug administration and type of animal preparation. In the present study, the effects of dopamine on the responses of wide dynamic range (WDR) cells to mechanical, thermal and graded electrical stimuli were investigated, and the dopamine-induced changes in WDR cell responses were compared between animals with an intact spinal cord and the spinal animals. Spinal application of dopamine (1.3 & 2.6 mM) produced a dose-dependent inhibiton of WDR cell responses to afferent inputs, the pinch-induced or the C-fiber evoked responses being more strongly depressed than the brush-induced or the A-fiber evoked responses. The dopamine-induced inhibition was more pronounced in the spinal cat than in the cat with intact spinal cord. The responses of WDR cell to thermal stimulation were also strongly inhibited. Dopamine D₂ receptor antagonist, sulpiride, but not D₁ receptor antagonist, significantly blocked the inhibitory action of dopamine on the C-fiber and thermal responses of dorsal horn cells. These findings suggest that dopamine strongly suppresses the responses of WDR cells to afferent signals mainly through spinal dopamine D₂ receptors and that spinal dopaminergic processes are under the tonic inhibitory action of the descending supraspinal pathways.

키워드

Dopamine WDR cell activity Spinal cat Descending dopaminergic inhibition