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- Title
Mathematical characterization of the afferent postdischarge period at the spinal dorsal horn.
- Authors
Bosco R; Eblen-Zajjur A
- Abstract
The nociceptive sensorial signals that enter the dorsal spinal horn (DH) through primary afferents, establish synaptic connections with neuronal circuits of itself, to which descendent supraspinal modulators pathways andlor propriospinals pathways converge too, exerting a powerful inhibiting or excitatory modulation of the nociceptive experience. Objective: to evaluate and characterize mathematicallythe postdischarge periods of the lumbar evoked potentials (LEP) of the DH in rats. Materials and methods: the experiments were done in male Sprague-Dawley rats; an electrical paired transcutaneal stimulus (20V; 0,2Hz; interstimulus latency of 1-200ms) was applied. Five pairs of LEP by each interestimulus interval were registered and stored; the Nand P waves generated by the second conditioner stimulus (Nc and Pc) were averaged. Results: for interstimuluslatencies <7.5 mstheinhibition ofthe Nc and Pc waves was absolute. The Nc wave showed a postdischarge inhibition period of 28ms and a supernormal period (110%) between 28-80ms of latency. The P wave maintained a constant increase of amplitude from 9.5ms without supernormal period. The relations between the interstimulus latency and the amplitude of the N and P waves is of polinomial character but with very different coefficients. Conclusions: the results suggest that excitatory and inhibitory postdischarge afferent periods in the DH surpass in duration the ones reported for fibers and individual neurons, brining additional evidence about the behavior of proprio and supraspinal neuronal circuits of afferent modulation at the DH.
- Publication
Archivos de Neurociencias, 2008, Vol 13, Issue 3, p155
- ISSN
1028-5938
- Publication type
Journal Article