Primary afferent-evoked synaptic responses and slow potential generation in rat substantia gelatinosa neurons in vitro

• DOI: 10.1152/jn.1989.62.1.96
• Publication Date: 2017-12-24T15:38:27Z
• Authors: M. Yoshimura; T. M. Jessell
• Keywords: Synaptic potential

1. Primary afferent fiber-evoked synaptic responses and the mechanisms of spike slow potential generation have been examined in adult rat substantia gelatinosa (SG) neurons an vitro transverse spinal cord slice preparation which attached dorsal root is retained. Intracellular recordings were made from SG identified by morphological electrophysiological criteria. Afferent fast excitatory postsynaptic potentials (fast EPSPs) EPSPs analyzed. 2. had mean resting membrane -67.1 +/- 0.5 mV (mean SE), input resistance 257 17.7 (SE) M omega, a time constant 21.3 1.9 ms exhibited spontaneous EPSPs. 3. Single low-intensity stimuli applied to using suction electrode produced, 70% neurons, short-latency, presumed monosynaptic half decay 10-30 amplitude 8-28 mV. The conduction velocity fibers evoking was 2-7 m/s, corresponding that thinly myelinated A-delta-fibers. Dorsal stimulation at higher intensities evoked, 10% long-latency apparently course similar evoked stimulation. 0.4-2 suggesting they constitute predominantly C-fibers. A-delta- C-fiber-mediated detected 20% examined. 4. Low-intensity produced neurons. Slow 3-15 up 2 min duration. A-delta-fibers appeared be responsible for associated with increase decreased hyperpolarization. 5. Action 76.3 1.1 duration 1.0 0.07 ms. Na+ ions represent main charge carrier during rising phase action Ca2+ contribute shoulder on falling phase. 6. In subthreshold depolarizing pulses followed long-lasting slow-inactivating able initiate spikes. blocked TTX enhanced application TEA Ba2+, K+ are involved this potential.(ABSTRACT TRUNCATED AT 400 WORDS)