Abstract
The 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.
Original language | English (US) |
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Pages (from-to) | 111-122 |
Number of pages | 12 |
Journal | Experimental Brain Research |
Volume | 62 |
Issue number | 1 |
DOIs | |
State | Published - Mar 1986 |
Keywords
- Bistable neuronal behavior
- Serotonin
- Spinal cord
- Stretch reflex
- Tonic vibration reflex
ASJC Scopus subject areas
- General Neuroscience