[Reflex suppression of evoked nociceptive responses in the parafascicular complex and posterior ventromedial nucleus of the thalamus in cats during electroacupuncture].

Acute experiments on cats have shown that electroacupuncture (EA) of auricular points inhibits the amplitude of evoked potentials (EP) induced by noxious stimulation of the tooth pulp in the parafascicular complex and the posterior ventromedial nucleus of the thalamus. The amplitude of evoked potentials in the parafascicular complex was inhibited by 70% of the control level, the effect lasting 40--50 min and being recovered by the control level in the next 50 min. The amplitude of evoked potentials in the posterior ventromedial nucleus of the thalamus was inhibited by 50% of the control level, the effect lasting 30 min, followed by the recovery to the control level in the next 20--30 min. The amplitude of EP induced by tactile stimulation of the mouth lip was not appreciably affected by EA. It is suggested that varying degrees of the inhibition of evoked nociceptive responses in specific and non-specific areas of the thalamus are determined by the features of functional organization of the afferent inputs.