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Biomedical subjects

R A Durinian

Publications and source records attributed to R A Durinian.

At least 19 recordsLinked to original sources
PubMed1986

[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. Partial lesion of the lateral and suprasylvian gyri, used as control, did not affect the efficiency of reflex analgesia. It is concluded that somatosensory areas of the cortex, especially 2, are involved in reflex analgesia.

Acupuncture Therapy↗
PubMed1986

[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.

Acupuncture Therapy↗
PubMed1986

[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. Schemes of possible organization of functional pools realizing the mechanisms of inhibition of nociceptive signals on central neurones during EAP way of reflex stimulation are suggested.

Acupuncture Therapy↗
PubMed1985

[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. The same results were obtained in an experiment with systemic injection of morphine (5 mg/kg). It is suggested that different parts of the caudal nucleus are responsible for the transmission of discriminative and diffuse components of the nociceptive signals to the specific and nonspecific projection systems. The oral nucleus may be involved in the transmission of signals about mouth lesions conveying the necessity for defense reactions.

Acupuncture Therapy↗
PubMed1985

[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.). After functional inactivation of the second somatosensory cortex electroacupuncture failed to facilitate the evoked potentials in the oral trigeminal nucleus by stimulation of the tooth pulp and the lip of the mouth. In the caudal nucleus, the inhibitory effect of electroacupuncture on noxious stimulation decreased. The involvement of this brain cortex in the mechanisms of action of electroacupuncture on functionally different nuclei is discussed.

Acupuncture Therapy↗
PubMed1984

[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. The neurons of the medial area displayed a significant (P less than 0.001) tendency of their dendrite orientation towards the sylvius aqueduct.

Animals↗
PubMed1983

[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. alpha-MPT did not influence the HP test latency after AEA, and HP or TF tests after stress. Inhibition of dopamine receptors by haloperidol produced a decrease in the stress- and AEA-induced analgesia. The similar effects were demonstrated in propranolol treated rats after AEA. P-chlorophenylalanine (an inhibitor of serotonin synthesis) suppressed the stress-induced analgesia measured by the HP test and AEA-induced analgesia measured by the HP or TF tests. The data indicate that the monoaminergic systems are involved in the stress- and AEA-induced analgesia. Apart from the monoaminergic systems, other neurochemical mechanisms are also involved in the stress- and AEA-induced analgesia.

Acupuncture Therapy↗
PubMed1983

[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.

Acupuncture Therapy↗
PubMed1983

[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. It is suggested that by stimulating the release of endogenous opiates and other neurotransmitters EAP remodels the function of the CNS afferent systems, facilitating the transmission of the non-nociceptive signal through the rapid-conducting lemniscal system, thereby blocking the transmission of the nociceptive signals in the multi-synaptic extralemniscal system.

Acupuncture Therapy↗
PubMed1982

[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.

Acupuncture Therapy↗
PubMed1982

[Reflex changes in the function of the cerebral cortex and central gray matter after electroacupuncture].

It was shown in acute experiments on cats exposed to single stimulation of different areas of the large hemispheric cortex that the second somatosensory zone (SP) has the most marked corticofugal connections with the central gray matter (CG). Electroacupuncture stimulation (EAS) in the area of the cat auricular basis (1.2 ms, up to 16 mA, 1-3 pulse/sec, 15-30 min) inhibited the evoked nociceptive responses in the P and facilitated them in the CG. The non-nociceptive evoked responses were facilitated by EAS both in the SP and CG. Upon SP cooling EAS did not facilitate the evoked non-nociceptive responses in the CG. It is suggested that the SP may play an important part in the activation of one of the main antinociceptive structures of the CG under EAS.

Acupuncture Therapy↗
PubMed1982

[Role of the central gray substance in activating the analgesic systems of the rat bran under stress].

Electrolytic lesions of central gray matter (CGM) were induced in rats. The analgesia produced by stress (foot shock) tested by the hot-plate and tail-flick method was significantly and substantially reduced in the lesioned rats. The baseline pain threshold measured by the hot-plate method was significantly longer in CGM-lesioned rats. The baseline tail-flick latency was unaffected by the lesions. The role of CGM in the regulation of pain sensitivity in rats is discussed.

Analgesia↗