Tokyo school life 18 patch
B: Example of responses of spontaneous discharges and of noxious pinch stimulation after subcutaneous injection of mustard oil (MO) into the receptive field area.
Arrow heads show resting membrane potential.
Blackened area indicates the location and size of the receptive field responding to noxious pinch stimulation.
#TOKYO SCHOOL LIFE 18 PATCH SKIN#
A: Noxious pinch stimuli applied to the orofacial skin (blackened area) produced a barrage of excitatory postsynaptic potentials (EPSPs) accompanied by action potentials in SI neurons (NS-type). The present study provides evidence that SI neurons in deep layers III-V respond to the temporal summation of EPSPs due to noxious mechanical and chemical stimulation applied to the orofacial area and that these neurons may contribute to the processing of nociceptive information, including hyperalgesia.Įffect of noxious chemical stimulation of the receptive field on the spontaneous discharges and noxious pinch-evoked responses. In the case of noxious chemical stimulation applied as mustard oil to the orofacial area, the membrane potential shifted depolarization and the rate of spontaneous discharges gradually increased as did the noxious pinch-evoked discharge rates, which were usually associated with potentiated EPSP amplitudes. Noxious mechanical stimuli applied to the receptive field elicited a discharge of action potentials on the barrage of EPSPs. In the majority of these neurons, a proportion of the excitatory postsynaptic potentials (EPSPs) reached the threshold, and then generated random discharges of action potentials. Nociceptive neurons were further divided into wide-dynamic range neurons (3/27, 11%) and nociceptive-specific neurons (18/27, 67%). Twenty-seven out of 63 neurons were identified in the mechanical receptive field of the orofacial area (36 neurons showed no receptive field) and they were classified as non-nociceptive (low-threshold mechanoreceptive 6/27, 22%) and nociceptive neurons. In vivo whole-cell current-clamp recordings were performed in rat SI neurons (layers III-IV). The aim of the present study was to examine whether noxious stimulation applied to the orofacial area evokes the synaptic response of SI neurons in urethane-anesthetized rats using an in vivo patch-clamp technique. Although it has been widely accepted that the primary somatosensory (SI) cortex plays an important role in pain perception, it still remains unclear how the nociceptive mechanisms of synaptic transmission occur at the single neuron level.