01802nas a2200217   4500008004100000022001400041245009300055210006900148260001200217300001400229490000700243520113900250653003101389653001401420653001601434653001901450653002701469100002301496700001801519856004701537       1986                        eng d  a0014-481900aEnhancement by serotonin of tonic vibration and stretch reflexes in the decerebrate cat.0 aEnhancement by serotonin of tonic vibration and stretch reflexes  c03/1986  a111–1220 v623 aThe effects of pharmacological manipulation of serotonergic systems on spinal reflexes were determined in the unanesthetized decerebrate cat. The prolonged motor output that continues after cessation of high frequency longitudinal tendon vibration was strongly enhanced by the serotonin reuptake blocker fluoxetine and the serotonin precursor 5-hydroxytryptophan, and was decreased by the serotonin receptor antagonist methysergide. In addition, both dynamic and static stretch reflex stiffness was markedly increased by fluoxetine and 5-hydroxytryptophan, while methysergide produced a decrease in stretch reflex stiffness. These powerful effects on tonic vibration and stretch reflexes could not be explained by drug-induced alterations in muscle spindle primary afferent discharge. In light of other recent results on serotonin-mediated effects on motoneurons, we believe that the effects of these agents result from modification of an intrinsically mediated prolonged depolarization of spinal neurons. However, the possibility that these drugs modify longlasting discharge in associated interneuronal pathways cannot be ruled out.10abistable neuronal behavior10aserotonin10aSpinal Cord10astretch reflex10atonic vibration reflex1 aCarp, Jonathan, S.1 aRymer, W., Z.  uhttp://www.ncbi.nlm.nih.gov/pubmed/3007191