Adrenergic Receptors Modulate Motoneuron Excitability, Sensory Synaptic Transmission and Muscle Spasms After Chronic Spinal Cord Injury
MM Rank, KC Murray, MJ Stephens, J D'Amico, MA Gorassini, DJ Bennett
JOURNAL OF NEUROPHYSIOLOGY | AMER PHYSIOLOGICAL SOC | Published : 2011
The brain stem provides most of the noradrenaline (NA) present in the spinal cord, which functions to both increase spinal motoneuron excitability and inhibit sensory afferent transmission to motoneurons (excitatory postsynaptic potentials; EPSPs). NA increases motoneuron excitability by facilitating calcium-mediated persistent inward currents (Ca PICs) that are crucial for sustained motoneuron firing. Spinal cord transection eliminates most NA and accordingly causes an immediate loss of PICs and emergence of exaggerated EPSPs. However, with time PICs recover, and thus the exaggerated EPSPs can then readily trigger these PICs, which in turn produce muscle spasms. Here we examined the contrib..View full abstract
Awarded by National Institute of Neurological Disorders and Stroke
Awarded by NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
Funding was provided by National Institute of Neurological Disorders and Stroke Grants RO1 NS-47567-01 to D. J. Bennett and RO1 NS-48170-01 to M. A. Gorassini, Canadian Foundation for Innovation, the Canadian Institutes of Health Research, and the Alberta Heritage Foundation for Medical Research. The authors acknowledge Recordati S.p.A (Milano, Italy) for the generous donation of REC15/2739.