Motor SystemsNO donor SIN-1 potentiates monosynaptic reflexes in the cat spinal cordManjarrez, ElíasCA; Rocha, Teresa1; Rojas-Piloni, Gerardo; Méndez, Ignacio; Vélez, Daniel1; Flores, AmiraAuthor Information Instituto de Fisiología and 1Facultad de Medicina, Benemérita Universidad Autónoma de Puebla, 14 sur 6301, Col. San Manuel, Apartado Postal 406. Puebla, Pue. CP 72570, México CACorresponding Author Received 26 May 2001; accepted 12 June 2001 Neuroreport: August 28th, 2001 - Volume 12 - Issue 12 - p 2667-2671 Buy SDC Abstract The effect produced by the nitric oxide donor SIN-1 on monosynaptic reflexes was examined. Experiments were performed on anesthetized, paralyzed and spinalized cats. Lumbar monosynaptic reflexes were produced by stimulation of Ia afferents. I.v. application of SIN-1 (500 μg/kg) produced a mean marked potentiation of 704% of pre-drug control (100%) in the amplitude of monosynaptic reflexes. In addition, in other experiments a concentration-dependent effect on the ampli- tude of monosynaptic reflexes was observed after microinjections of SIN-1 into the ventral horn (1 μl; 10−12–10−3 M), with a mean facilitatory effect of 355%. In both cases, the potentiation was reversible 45 min after i.v. or local application of SIN-1. These results provide the first evidence that monosynaptic reflexes can be potentiated by nitric oxide. © 2001 Lippincott Williams & Wilkins, Inc.