Properties of Rhythmic Activity Generated by the Isolated Spinal Cord of the Neonatal Mouse

• DOI: 10.1152/jn.2000.84.6.2821
• Publication Date: 2017-12-21T08:42:11Z
• Authors: Patrick Whelan; Agnes Bonnot; Michael J. O'Donovan
• Keywords: 0301 basic medicine; Periodicity; Serotonin; N-Methylaspartate; Cauda Equina; Sacrococcygeal Region; Dopamine; Lumbosacral Region; In Vitro Techniques; Motor Activity; Receptors, N-Methyl-D-Aspartate; Electric Stimulation; Hindlimb; Drug Combinations; Mice; 03 medical and health sciences; Animals, Newborn; Spinal Cord; Animals; Receptors, AMPA; Muscle, Skeletal; Spinal Nerve Roots

We examined the ability of isolated lumbosacral spinal cord neonatal mouse (P0–7) to generate rhythmic motor activity under several different conditions. In absence electrical or pharmacological stimulation, we recorded patterns spontaneous ventral root depolarization and discharge. Spontaneous, alternating discharge between contralateral roots could occur two three times over a 10-min interval. also observed other patterns, including left-right synchrony restricted one side cord. Trains stimuli delivered lumbar/coccygeal dorsal sural nerve reliably evoked episodes activity. During these episodes, discharges on alternate from side. Bath application combination N-methyl-d,l-aspartate (NMA), serotonin, dopamine produced that last for hours. Under conditions, left right L 1 –L 3 alternated. 4 5 segments, had peaks in each cycle, coincident with ipsilateral roots. The 6 alternated established drug-induced rhythm was locomotor-like by recording an pattern flexor extensor hindlimb muscle nerves. addition, simultaneously nerves, ankle phase /L 2 discharge, while Rhythmic were preserved following mid-sagittal section cord, demonstrating reciprocal inhibitory connections sides are not essential rhythmogenesis Blocking N-methyl-d-aspartate receptors, both intact hemisected preparation, revealed receptors contribute but rhythmogenesis. contrast, abolished blockade kainate/AMPA 6-cyano-7-nitroquinoxalene-2,3-dione. These findings demonstrate can produce variety coordinated activities, study behaviors conditions offers promise future studies rhythmogenic mechanisms this preparation.