Peptidergic neuromodulation of the lumbar locomotor network in the neonatal rat spinal cord.
Peptides. 2005-02-01; 26(2): 277-286
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It is now well established that a dynamic balance of neurotransmitters and
neuromodulators finely influence the output of neuronal networks and subsequent
behaviors. In the present study, to further understand the modulatory processes
that control locomotor behavior, we investigated the action of 11 neuropeptides,
chosen among the various peptide subfamilies, on the lumbar neuronal network in
the in vitro neonatal rat spinal cord preparation. Peptides were bath-applied
alone, in combination with N-methyl-D,L-aspartate (NMA) or with the classical
‘locomotor cocktail’ of NMA and serotonin. Using these different experimental
paradigms, we show that each peptide can neuromodulate the lumbar locomotor
network and that peptides exhibit different neuromodulatory profiles and
potencies even within the same family. Only vasopressin, oxytocin, bombesin and
thyrotropin releasing hormone triggered tonic or non-organized rhythmic
activities when bath-applied alone. All the neuropeptides modulated NMA induced
activity and/ or ongoing sequences of fictive locomotion to varying degrees.
These results suggest that neuropeptides play an important role in the control of
the neural network for locomotion in the neonatal rat. Their various profiles of
action may account in part for the great flexibility of motor behaviors.
PMID: 15629539 [Indexed for MEDLINE]