[Effect of electroacupuncture on the integration of nociceptor and non-nociceptor afferent pathways in the second somatosensory cortex of the cerebral hemisphere].

It was shown in acute experiments on cats tha auricular electroacupuncture (EA) at a frequency of 3 Hz for 15-30 minutes produces an inhibition of evoked potentials (EP) in response to nociceptive stimulation of the dental pulp in the second somatosensory zone of the large hemispherical cortex (C2) up to 40% of the control level. The effect lasts 50-60 minutes. The inhibitory effect is abolished by intravenous injection of naloxone (5 mg/kg). Along with inhibition of nociceptive EP, EA facilitates EP by 75% upon non-nociceptive stimulation of the lower lip for 15-20 minutes. Direct stimulation of C2 produces an inhibition of nociceptive EP in the parafascicular complex of the thalamus. It is suggested that EA stimulates the neuronal populations of C2, which enhances the modulating effects of this zone of the cortex on the transmission of nociceptive information at various levels of the CNS.