[The opiate mechanism of transcranial electroanalgesia in rats and mice]. / Ob opiatnom mekhanizme transkranial'noi élektroanalgezii u krys i myshei.

In partially restrained alert rats and mice, the opioid mechanism of the transcranial electroanalgesia was investigated. Naloxone (0.5-2.0 mg/kg) reversibly suppressed the electroanalgesia in rats. The electroanalgesic effect in rats tolerant to morphine in doses 5-10 mg/kg, was absent. The involvement of endogenous opioid mechanisms in electroanalgesia was confirmed by enhancing of the analgesia with D-phenylalanine (350 mg/kg). The findings suggest that analgesic effect is based on transcranial electrical stimulation of opioid mechanisms. Investigation of endogenous opioid mechanisms in different antinociceptive brain structures in experimental models of transcranial electroanalgesia, is discussed.

[Effect of 5,7-dihydroxytryptamine on pain sensitivity and analgesic activity of morphine]. / Vliianie 5,7-digidroksitriptamina na bolevuiu chuvstvitel'nost' i boleutoliaiushchee deistvie morfina.

Electron microscopy of rats ultrathin sections from dorsal and central raphe nucleus and spinal cord after 5,7-dihydroxytryptamine intracisternal microinjection (200 micrograms) has revealed neurones and axonal terminals distruction, which associated with tail-flick hypoalgesia and blood pressure nociceptive reactions diminished. In this condition the morphine (2 mg/kg) analgesia and drug depressive effect on pain hemodynamic manifestations increase significantly.

[Effect of opiate agonists administered intrathecally on the behavioral and hemodynamic manifestations of pain]. / Vliianie opiatnykh agonistov pri ikh intratekal'nom vvedenii na povedencheskie i gemodinamicheskie proiavlenbiia boli.

An agonist of mu-opiate receptors, D-Ala2-Gly-ol5-enkephalin (DAGO, 0.5 mcg), administered intrathecally, was found to inhibit behavioral and hemodynamic reactions induced by thermal and electrical stimulation of conscious male rats. D-Ala2-D-Leu-enkephalin (DADL, 0.5 mcg), acting on delta-receptors, was shown to potentiate nociceptive shifts of arterial blood pressure. Phencyclidine and bremazocine failed to exert any significant effect on the opioidergic mechanisms of the spinal cord.

[A new principle in the analysis of the analgesic action of morphine]. / Novyi printsip analiza boleutoliaiushchego deistvia morfina.

Possible application of sensory decision theory of pain for the experimental assessment of neuropsychophysiological mechanisms of opiate analgesia has been demonstrated. The analgetic effect of morphine was found to be mediated through the influence on the measurement and estimation of pain stimulus.

[Effect of morphine and pentazocine on emotional-behavioral and hemodynamic nociceptive reactions]. / Vliianie morfina i pentazotsina na émotsional'no-povedencheskie i gemodinamicheskie notsitseptivnye reaktsii.

Pentazocine (5-15 mg/kg) fails to change the period of latency in the rat tail-flick reaction at thermic stimulation but suppresses to the same extent as morphine (5 mg/kg) the emotional-pain response and enhances the reactions of arterial blood pressure during mechanical stimulation. Both prazosin and naloxone (1 mg/kg) abolished the activating effect of pentazocine on the arterial blood pressure changes produced by nociceptive stimulation.

[Influence of klofelin on the analgesic effect of morphine]. / Vliianie klofelina na anal'geticheskii éffekt morfina.

It has been revealed on conscious rats that it is possible to decrease the dose of morphine and to facilitate the vegetocorrective component of the drug effect without analgesia changes using the combination with klofelin . The effect of the combined use of morphine and klofelin has been found to be mediated by the common adrenergic but not opioidergic substrate.