[The analgesic action of narcotic analgesics and clopheline after the ionizing irradiation of rats]. / Boleutoliaiushchee deistvie narkoticheskikh anal'getikov i klofelina posle ioniziruiushchego oblucheniia krys.

The ionizing radiation (150 Gy) extended the rat tail flick latency, decreased the pain-relief effects of morphine and opioids and enhanced the analgesic effect of clopheline. The radiation was followed by a decrease of vocalization threshold with a reduction of morphine- and clopheline-induced analgesia. Naloxone (0.1 mg/kg) eliminated the postradiation analgesia and did not change the hyperalgesic effect of the radiation.

[The effect of analgesics on hemodynamic indices following irradiation with high doses]. / Vliianie boleutoliaiushchikh sredstv na nekotorye pokazateli gemodinamiki posle oblucheniia v vysokikh dozakh.

With radiation doses of 10 and 150 Gy morphine does not change the arterial tension and the pressor nociceptive reactions of rats. Clopheline delivered in an analgesic dose invokes a pressor reaction of the haemodynamics after irradiation with a dose of 10 Gy, but it is ineffective after superlethal doses.

[The effect of irradiation in lethal and highly lethal doses on arterial pressure and hemodynamic nociceptive reactions]. / Vliianie oblucheniia v letal'noi i sverkhletal'noi dozakh na arterial'noe davlenie i notsitseptivnye reaktsii gemodinamiki.

It has been found that the effect of whole-body gamma-irradiation with doses of 10 and 150 Gy on the haemodynamics regulation varies. Thus, the dose of 10 Gy does not change the arterial tension and the dose of 150 Gy decreases the arterial tension 6 and 24 hr after irradiation, the nociceptive reactions of haemodynamics being invariable with both doses.

[Pharmacologic correction of postradiation changes of pain sensitivity in rats]. / Farmakologicheskaia korrektsiia postluchevykh izmenenii bolevoi chuvstvitel'nosti u krys.

With radiation injury caused by superlethal doses of 150 Gy the analgesic effect of narcotic drugs decreases and the level of drug analgesia depends on the initial status of nociceptive reactions. The role of mu-opiate mechanisms in the development of postirradiation analgesia to thermal stimuli has been determined.

[Effects of morphine and naloxone on pain sensitivity after radiation injuries in rats]. / Vliianie morfina i naloksona na bolevuiu chuvstvitel'nost' posle luchevogo porazheniia krys.

Radiation in doses 150 Gy induces different changes in pain sensitivity in rats by thermal (analgesia) and electrical (hyperalgesia) stimuli. Naloxone (0.1 and 1 mg/kg) and morphine (5 mg/kg) show, that analgesia is realized due to opioid mechanisms.

[The central regulation of pain sensitivity in rats after irradiation with high doses of ionizing radiation]. / Tsentral'naia reguliatsiia bolevoi chuvstvitel'nosti u krys posle oblucheniia vysokimi dozami ioniziruiushchikh izluchenii.

It was shown that during 24 h following whole-body exposure of male rats to gamma-quanta (150 Gy) the latent period of their response to the thermal effect increased a "tail-flick" test) and the threshold of the nociceptive response to an electric stimulus (the vocalization threshold) decreased. A correlation was found between the initial response to the nociceptive effects and variation of these values in irradiated animals.

[Effect of gamma-radiation of an extremely high dose on the cerebral cortex of the rat (ultrastructural aspects)]. / Vliianie gamma-radiatsii v sverkhvysokoi doze na koru bol'shogo mozgakrysy (ul'trastrukturnye aspekty).

For 24 h after total gamma-radiation of mature Wistar male rats (180-210 g) in the dose of 150 Gy, ultrastructural rearrangements of the cerebral sensomotor cortex are presented as small destructive changes in neurons, neuroglia and vascular endothelium. Total combination of the changes in ultrastructure of the blood capillaries and perivascular astrocytes makes it possible to suppose that permeability of the microvascular bed wall is increased. At this period, together with the destructive changes there are evidently certain compensatory-restorative processes, developing in the cerebral tissue. It is possible to suppose that already during the first hours after the radiation the ultrastructural changes of neurons are resulted not only from the direct effect of radiation, but from certain influences of the radiation damage of neuroglia and microvessels.

[Early changes in the ultrastructure of axodendritic synapses in the rat sensorimotor cortex following whole-body irradiation with high-dose fast neutrons]. / Rannie izmeneniia ul'trastruktury aksodendriticheskikh sinapsov sensomotornoi kory krysy posle obshchego oblucheniia bystrymi neitronov v vysokoi doze.

Changes in morphometric parameters have been established in axodendritic synapses of sensorimotor cortex of adult mature rats exposed to neutron irradiation. Neutron irradiation dose and summarized dose rate were 10 Gy and 0.35 Gy, respectively. The changes were observed 0.25, 1, 3, 6 and 24 hours after irradiation. The observations suggest an increase in synaptic activity, with the range of irradiation action and functional characteristics decreasing in subsequent time periods.

[Relation between the dynamics of early ultrastructural changes in the cerebral cortex of the rat and radiation dose]. / Zavisimost' dinamiki rannikh ul'trastrukturnykh izmenenii kory bol'shogo mozga krysy ot dozy radiatsionnogo vozdeistviia.

The electron microscopic investigation of the sensomotor zone in the cerebral cortex of mature male rats after total neutron and gamma radiation of high doses has demonstrated, that during first three hours after the influence the dynamics of ultrastructural changes in neurons, glial elements and microcirculatory bed depends on the radiation dose. After gamma radiation of 150 Gy, destructive changes in neurons, increased permiability of blood capillaries and development of perivascular edema are noted at earlier time than after radiation dose of 10 Gy. When the greater dose of radiation is used, also earlier reaction of the barrier structures in the brain is observed.

[Indices of the status of the cholinergic processes in the rat sensorimotor cortex and caudate nucleus at early periods after gamma-irradiation at a dose of 150 Gr]. / Issledovanie nekotorykh pokazatelei sostoianiia kholinérgicheskikh protsessov v sensomotornoi kore i khvostatom iadre golovnogo mozga krys v rannie sroki posle gamma-oblucheniia v doze 150 Gr.

An insignificant increase in the content of acetylcholine-like substances was registered in the rat brain cortex and caudate nucleus 15 min after whole-body gamma-irradiation with a dose of 150 Gy. After 24 h, the number of these substances appreciably decreased. Total acetylcholinesterase activity in the above brain parts gradually decreased throughout the entire period of observation. These indices changed more markedly in the caudate nucleus than in the cortex of the brain.

[Dynamics of changes in the ultrastructure of the rat cerebral cortex in the early period of acute radiation sickness caused by neutron irradiation]. / Dinamika izmenenii ul'trastruktury kory golovnogo mozga krys v rannie sroki ostroi luchevoi bolezni, vyzvannoi neitronnym oblucheniem.

A 24-hour electron microscopic examination of neuronal and capillary ultrastructure in sensorimotor complex was performed after whole-body neutron irradiation of mature rats in the dose of 10 Gy. The results suggest that postradiation neuronal changes, observed for 6 hours after irradiation, are mainly caused by direct effect of ionizing radiation. At later terms this process is influenced by blood capillary lesions. The effect of neutron irradiation at the ultrastructural level is similar to that of rarely ionizing radiation.

[Dynamics of the early ultrastructural changes in sensorimotor cortical neurons of the rat brain after exposure to high doses of gamma-neutron radiation]. / Dinamika rannikh izmenenii ul'trastruktury neironov sensomotornoi zony kory golovnogo mozga krys posle deistviia vysokikh doz gamma-neitronnogo izlucheniia.

At early times (15 min to 6 h) after whole-body gamma-neutron irradiation of mature rats with a dose of 10 Gy reactive changes occur in neurons of the sensimotor cerebral cortex which can be interpreted as a manifestation of the enhancement of functional and metabolic activity of nerve cells followed by inhibition thereof.

[Electron microscopy study of microcirculation in the rat cerebral cortex after total neutron irradiation]. / Elektronno-mikroskopicheskoe issledovanie mikrotsirkuliatornogo rusla kory golovnogo mozga krysy posle obshchego neitronnogo oblucheniia.

It was established that the ultrastructure of blood capillaries of the brain changes during the first six hours following whole-body neutron irradiation of rats (10 Gy) which was indicative of the capillary wall swelling, the increase in the microcirculatory bed permeability, and pericapillary edema development. Those processes seemed to be reversible since during this period no severe destructive changes were detected in the microvessel wall.