Peptidergic neuromodulation of the lumbar locomotor network in the neonatal rat spinal cord.
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.
Barrière
Grégory
G
CNRS UMR 5543, Physiologie et Physiopathologie de la Signalisation Cellulaire, Université Victor Segalen Bordeaux 2, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France.
Bertrand
Sandrine
S
Cazalets
Jean-René
JR
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001839:Bombesin / Q000494:pharmacology; D001920:Bradykinin / Q000494:pharmacology; D004357:Drug Synergism; D004744:Enkephalin, Methionine / Q000494:pharmacology; D019835:FMRFamide / Q000494:pharmacology; D005727:Ganglia, Spinal / Q000502:physiology; D008124:Locomotion / Q000187:drug effects / Q000502:physiology*; D008161:Lumbosacral Region / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects*; D016202:N-Methylaspartate / Q000494:pharmacology; D009415:Nerve Net / Q000502:physiology*; D009479:Neuropeptides / Q000494:pharmacology; D009496:Neurotensin / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology; D010121:Oxytocin / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*; D013972:Thyrotropin / Q000494:pharmacology; D014667:Vasopressins / Q000494:pharmacology
D009479:Neuropeptides; D018377:Neurotransmitter Agents; D009842:Oligopeptides; D014667:Vasopressins; D000804:Angiotensin II; D012701:Serotonin; D009496:Neurotensin; D010121:Oxytocin; C011536:proctolin; D004744:Enkephalin, Methionine; D016202:N-Methylaspartate; D019835:FMRFamide; D013972:Thyrotropin; D001839:Bombesin; D001920:Bradykinin