[The role of the somatosensory cortex in the development of reflex analgesia].

The effects of reflex stimulation on the changes of nociception thresholds in animals before and after ablation of the somatosensory cortex were studied in behavioural experiments on adult cats. Electroacupuncture stimulation (EAP) was shown to increase nociception thresholds at all levels of the conventional scale. The ablation of both the first (S1) and the second (S2) somatosensory cortex led to EAP inefficiency at the side opposite to the ablation.

[Functional architectonics of neuronal antinociceptive mechanisms during the electroacupuncture method of reflex action].

The peculiarities of neurone bioelectric activity of sensory thalamic nuclei under electroacupuncture (EAP) stimulation have been studied in acute experiments on cats. EAP stimulation has been established to change spontaneous and evoked activity of neurones of sensory thalamic nuclei, that testifies to the development of a new functional state. The functional state of the cortex, in particular the second somatosensory region has been shown to determine the nature of neurone activation of sensory thalamic nuclei during the EAP stimulation.

[Somatosensory evoked potentials and their dynamics among trigeminal neuralgia patients during reflexotherapy].

The study of somatosensory evoked potentials (SSEP) in patients with trigeminal neuralgia made it possible to elucidate their characteristic changes as compared to those in healthy subjects. After a course of acupuncture 75% of the patients showed correlation between some parameters of SSEP and positive clinical results. The authors discuss pathophysiological mechanisms of impairment of cortico-subcortical interactions in patients with trigeminal neuralgia and analyze the possibility of using SSEP for dynamic evaluation of the brain status in the process of treatment.

[Modulating influence of the 2d somatosensory cortex of the cerebral cortex on the effects of electroacupuncture on the trigeminal nuclei].

The effect of reversible functional inactivation of the second somatosensory cortex of the cerebral hemispheres on changes in the transmission of the afferent signals in the trigeminal nuclei after electroacupuncture was studied in acute experiments on adult cats anesthetized with hexenal (59 mg/kg i. p.).

[Effect of electroacupuncture and morphine on evoked potentials in the oral and caudal trigeminal nuclei in the cat].

Electroacupuncture effects on the functions of the oral and caudal trigeminal nuclei were comparatively analyzed in acute experiments on cats narcotized by hexinal (50 mg/kg). Responses evoked in the caudal nucleus by tooth pulp stimulation were inhibited while responses to mouth mucosa stimulation remained unchanged. In the oral nucleus responses to both types of stimulation were relieved.

[Effect of morphine on the change in the nociceptive and non-nociceptive evoked potentials in the orbitofrontal and secondary somatosensory areas of the cerebral cortex in different functional states].

The effect of morphine on alterations in nociceptive and non-nociceptive evoked potentials (EP) elicited in the second somatosensory (S2) and orbito-frontal cortex of the brain was studied in acute experiments on cats. Administration of morphine in a dose of 5 mg/kg to the above-mentioned structures caused an increase in the amplitude of EP to non-nociceptive stimulation and a decrease of EP to nociceptive stimulation. Under alternate functional inactivation of the orbito-frontal cortex and S2 a unidirectional effect of the projection cortex on the associative orbito-frontal cortex was observed, manifested by a decrease of EP in the orbito-frontal cortex.

[Features of the neuronal organization of the periaqueductal gray substance of the midbrain in the cat].

On the basis of morphological investigations two areas were distinguished in the periaqueductal grey of the cat midbrain: medial, directly surrounding the sylvius aqueduct and containing small neurons with significant (P less than 0.001) prevalence of fusiform cells and lateral with larger neurons, where triangular cells were significantly (P less than 0.001) prevalent.

[Reflexogenic changes in the spontaneous and evoked activity of the parafascicular neurons in the rat thalamus during electroacupuncture stimulation].

Acute experiments on cats were made to study the electroacupuncture (EAP) effect on neuronal impulse activity in the parafascicular complex (PFC) of the thalamus in response to solitary peripheral nociceptive and non-nociceptive stimuli. EAP stimulation affects the pattern of spontaneous and evoked activity of PFC neurons and forms their new functional status. It is suggested that the analgetic effect is brought about by the changes in neuronal activity in subcortical structures of the brain including the thalamic nuclei which transmit the ascending nociceptive input.

[Role of the somatic monoaminergic systems in the mechanisms of regulation of pain sensitivity during reflex stimulation].

Experiments on rats were performed to study the role of the monoaminergic systems in the mechanisms of analgesia produced by stress (foot shock) and auricular electroacupuncture (AEA). Analgesia was measured by the hot-plate (HP) and the tail-flick (TF) tests. Inhibition of catecholamine synthesis with alpha-methyl-p-tyrosine (alpha-MPT) antagonized the AEA-induced analgesia measured by the TF test.

[Changes in the bioelectric activity in the orbitofrontal and somatosensory areas of the cerebral cortex caused by electroacupuncture].

Effects of electroacupuncture (EAP) and intravenous injection of morphine (5 mg/kg) on evoked potentials (EP) elicited in the second somatosensory (S2) and orbitofrontal areas of the brain cortex by nociceptive (the pulp of the upper canine) and non-nociceptive (the upper lip) stimulation were studied in acute experiments on cats. After EAP the EP elicited by nociceptive stimulation of the S2 and orbital gyrus were inhibited 75 and 58%, respectively, with reference to the control level, whereas the EP elicited by non-nociceptive stimulation of the S2 and orbital gyrus rose by 30 and 45%, respectively. Morphine injection produced the same effect on the EP: an increase in the EP during non-nociceptive stimulation and inhibition during nociceptive stimulation.