Peculiarities of the development of analgesic effect during transcutaneous dynamic electrical stimulation.

The effect of transcutaneous dynamic electrical neurostimulation on the development of analgesia was studied in behavioral and electrophysiological experiments on rats. A 30-min dynamic electrical stimulation elevated the nociception threshold in tail-flick and hot plate tests, increased the threshold of the late nociceptive flexor reflex, and decreased the number of bursts in the response. Intraperitoneal injection of naloxone (2 mg/kg) abolished the analgesic effect of dynamic electrical neurostimulation. It is concluded that the key role in reflex analgesia during dynamic electrical neurostimulation is played by the endogenous cerebral opioid system, which inhibits the nociceptive signals traveling to CNS via unmyelinated C-fiber afferents.

[The effects of L-arginine in chronic pain syndromes]. / Effekty L-arginina pri khronicheskikh bolevykh sindromakh.

The effect of L-arginine in long-term parenteral administration was studied on a model of neuropathic pain syndrome and adjuvant arthritis. L-arginine produced a preventive and therapeutic effect in the neuropathic pain syndrome. It weakened the development of adjuvant arthritis for the period of its administration. The factor underlying the effect of L-arginine is its double action as a precursor of nitrous oxide and kiotorphin, an endogenous antinociceptive dipeptide.

[Clinical course and treatment of herpetic trigeminal ganglionic neuropathy]. / Klinika i lechenie gerpeticheskoi ganglionevropatii]

45 patients were observed in the periods of both acute herpes zoster and postherpetic neuralgia (PHN). In most of the patients herpetic eruptions were located in the areas of innervation of the first branch of the trigeminal nerve. In acute period of the disease there were used aciclovir, helepin or alpisarinum, antiherpetic immunoglobulin, deoxyribonuclease, non-narcotic analgetics were used. Of 28 patients residual PHN was observed in 6 cases, delayed PHN (during 3 months)--in 2 patients. The PHN development was characteristic for elderly patients, delayed request for medical care, concomitant diseases, eruptions with hemorrhagic component and secondary pyodermia and considerable residual sensory deficit. In therapy of PHN the most effective drugs were amitriptylin, non-narcotic analgetics, anticonvulsants as well as acupuncture and electroacupuncture. Relief of a typical deafferentation of pain syndrome was achieved by means of ultrasonic destruction of the trigeminal nucleus (one case). Early therapy of acute herpes zoster does not prevent completely PHN development, but it decreased considerably probability of its forming as well as the severity of its course.

[A clinical and experimental study of the role of long-lasting perioperative epidural anesthesia in the prevention of phantom limb pain]. / Kliniko-éksperimental'noe issledovanie roli dlitel'noi perioperatsionnoi épidural'noi anestezii v profilaktike fantomno-bolevogo sindroma.

The aim of this study was to investigate the possible onset of phantom limb pain (PLP) and its development depending on preoperative limb pain and type of anesthesia during limb amputation. It was experimentally proved that preliminary local anesthesia of rat sciatic nerve slowed down the development of pain syndrome after the operation as well as reduced the number of rats with pain syndrome, as compared to the group subjected to preliminary painful electrical stimulation of the operated on limb. The clinical data presented reveal a significant reduction in the incidence of PLP after perioperative epidural anesthesia, as compared to patients with preoperative pain operated on under general anesthesia.

[Morphine does not prevent the development of a pain syndrome in rats induced by transection of the sciatic nerve]. / Morfin ne predotvrashchaet razvitie bolevogo sindroma u krys, vyzvannogo pererezkoi sedalishchnogo nerva.

The effects of morphine on the development of the neurogenic pain syndrome were studied in rats after sciatic nerve dissection. Morphine was injected subcutaneously in doses of 0.1, 1.0, and 5.0 mg/kg every day, starting on the first day after dissection. It has been shown that despite the fact that morphine initially arrests the development of the pain syndrome, then it intensifies its course. Possible mechanisms responsible for the inefficacy of morphine in neurogenic pain syndromes are discussed.

[Effects of the removal of the orbito-frontal cortex on the development of reflex analgesia]. / Vliianie udaleniia orbito-frontal'noi kory na razvitie reflektornoi anal'gezii.

The authors studied the effect of electric acupuncture stimulation (EAP) on the changes in pain thresholds prior to and after removal of the orbito-frontal cortex (OFC) of the brain in behavioral experiments on adult cats. Removal of OFC increased the thresholds of pain response at the 4th and the 5th levels of the conventional scale, reflecting emotionally-affective manifestations of pain, and intensified the effect of antinociceptive EAP. The results obtained are analysed in relation to the inhibitory tonic effect of OFC on antinociceptive structures of the brain. Different effects of OFC and somatosensory cortex on the antinociceptive structures of the brain are discussed.

[Effect of electroacupuncture on the nature of changes in the activity of neurons in the 2d somatosensory region of the cerebral cortex]. / Vliianie élektroakupunktury na kharakter izmeneniia aktivnosti neironov vtoroi somatosensornoi oblasti kory bol'shikh polusharii.

Effects of electroacupuncture (EAP) on the character of spontaneous and evoked neuronal impulse activity changes in the second somatosensory area (S2) of the brain cortex by nociceptive and non-nociceptive stimulation were studied in acute experiments on cats. It was demonstrated that EAP changed the character of S2 neurons activity and formed their new functional state. After EAP activity of non-nociceptive neurons were not changed, evoked activity of nociceptive neurons were inhibited. It is suggested, that EAP preferential blocking the protopathic components of the acute pain.

[The role of the somatosensory cortex in the development of reflex analgesia]. / Znachenie somatosensornoi kory golovnogo mozga v razvitii reflektornoi analgezii.

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.

[Changes in the bioelectric activity in the orbitofrontal and somatosensory areas of the cerebral cortex caused by electroacupuncture]. / Izmenenie bioélektricheskoi aktivnosti v orbito-frontal'noi i somatosensornoi oblastiakh kory pri élektroakupunkturnom vozdeistvii.

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.