Switching-on and -off of bistable spontaneous discharges in rat spinal deep dorsal horn neurons.
Somatosensory deep dorsal horn spinal neurons were previously shown to present in vitro a bistable state of activity in which a fixed firing rate is maintained over prolonged periods in the absence of stimulation. Those periods of enhanced spinal spontaneous discharge may play a role in the genesis or maintenance of hyperalgesic states, where episodes of durable spontaneous pain are commonly reported. Here we show in vivo that a small percentage of deep spinal neurons (4% of the recorded population) are capable of rapidly shifting between low-frequency and high-frequency levels of spontaneous activity. At least one of the transitions between the two states was induced by stimulation of the receptive field, making this an interesting and unique case in which stable firing rates are switched-on or -off by somatosensory stimuli.
Monteiro
Clara
C
Laboratory of Molecular Cell Biology, Faculty of Medicine, University of Porto, Porto, Portugal; IBMC - Institute for Molecular and Cell Biology, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
Lima
Deolinda
D
Galhardo
Vasco
V
D000200:Action Potentials; D000818:Animals; D005557:Formaldehyde; D008297:Male; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology; D010812:Physical Stimulation; D020671:Posterior Horn Cells / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013331:Strychnine; D014110:Touch
D005557:Formaldehyde; D013331:Strychnine