Interstitial potassium concentration, slow depolarization and focal potential responses in the dorsal horn of the rat spinal slice.
Extracellular potassium concentration ([K+]o) was measured, and intra- and extracellular recordings made, in the dorsal horn of rat spinal cord slices maintained in vitro during repetitive dorsal root stimulation. In about half of the dorsal horn neurons, the stimulation evoked a possibly substance P-mediated slow depolarization. [K+]o increased during stimulation, reaching its highest values approximately 150 micron from the dorsal surface. The time course of delta [K+]o was different from that of the slow depolarization. Substance P itself evoked a much smaller delta [K+]o (0.4 mM) in the dorsal horn. It is concluded that the slow depolarization is not mediated by elevated [K+]o.
Urbán
L
L
Aitken
P G
PG
Somjen
G G
GG
D000818:Animals; D005110:Extracellular Space / Q000032:analysis; D066298:In Vitro Techniques; D008564:Membrane Potentials; D011188:Potassium / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000502:physiology*; D013373:Substance P / Q000502:physiology; D009435:Synaptic Transmission
D013373:Substance P; D011188:Potassium