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Proceedings of the Royal Society B: Biological Sciences logoLink to Proceedings of the Royal Society B: Biological Sciences
. 1998 Nov 7;265(1410):2073–2080. doi: 10.1098/rspb.1998.0542

Serotonin-induced inhibition of locomotor rhythm of the rat isolated spinal cord is mediated by the 5-HT1 receptor class.

M Beato 1, A Nistri 1
PMCID: PMC1689497  PMID: 9842733

Abstract

The neurotransmitter serotonin (5-HT) induces rhythmic motor patterns (fictive locomotion) of the neonatal rat spinal cord in vitro; this is a useful experimental model to study the generation of a motor programme at exclusively spinal level. Nevertheless, 5-HT slows down the fictive locomotion typically elicited by activation of NMDA glutamate receptors, suggesting a complex action of this monoamine. By means of electrophysiological recordings from multiple ventral roots we demonstrated that the decrease caused by 5-HT in NMDA-induced periodicity was dose-dependent, enhanced after pharmacological blocking of 5-HT2 excitatory receptors, and imitated by pharmacological agonists of the 5-HT1 receptor family. Selective blockers of the 5-HT1A or 5-HT1B/D receptor classes, either alone or in combination, largely (but not completely) attenuated this inhibitory action of 5-HT. It is concluded that the principal inhibitory action of 5-HT on the spinal locomotor network was mediated by certain subtypes of the 5-HT1 receptor class, which tends to oppose the 5-HT2 receptor-mediated excitation of the same network.

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Selected References

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