Effect of bradykinin and morphine on sensomotor cortical neurons in rats

Acute experiments on rats showed that bradykinin, injected by microiontophoresis, activates sensomotor cortical neurons in rats. Morphine, administered in the same way, prevents the development of the bradykinin effect. Bradykinin, it is suggested, acts on opiate receptors in cerebral cortical neurons.Laboratory of Pharmacology of the Nervous System, Institute of Pharmacology, Academy of Medical Sciences of the USSR. Laboratory of Emotions and Emotional Stresses, P. K. Anokhin Institute of Normal Physiology, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 10, pp. 450–452, October, 1978.     

Effect of morphine and azidomorphine on cortical unit activity

In acute experiments on unanesthetized curarized cats and rats morphine and azidomorphine, in analgesic doses, inhibited spontaneous and bradykinin-evoked unit activity in the sensomotor cortex. The depriming action of both drugs was abolished by nalorphine. It is suggested that the inhibitory action of morphine and azidomorphine is due to their direct action on the cerebral cortex.Laboratory of Pharmacology of the Nervous System, Institute of Pharmacology, Academy of Medical Sciences of the USSR. Department of Pharmacology, Faculties of Therapeutics and Environmental Health, I. M. Sechenov First Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 6, pp. 698–699, June, 1977.     

Effect of leucine-enkephalin on cerebral cortical unit activity

Experiments on unanesthetized rats immobilized with flaxedil showed that leucineenkephalin (150 g), if injected into the lateral cerebral ventricle, caused heterogeneous changes in the activity of 21 sensomotor cortical units tested. Spike discharges of five neurons were reduced and those of 11 neurons increased. Naloxone (2 mg/kg, intravenously) prevented both the inhibitor and the activating effect of leucine-enkephalin in the case of repeated injections of this pentapeptide. Leucine-enkephalin did not change the activity of five units.Department of Pharmacology, Faculties of Internal Medicine and Hygiene, I. M. Sechenov First Moscow Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 7, pp. 42–44, July, 1979.     

Action of naloxone on emotionally positive and antinociceptive effects of hypothalamic stimulation in rats

Naloxone (5 mg/kg, subcutaneously) had no significant effect on the electrical self-stimulation response in rats with electrodes in the lateral hypothalamus. An analgesic effect of stimulation of the reward zones was found in three animals, in the form of raising of the threshold of pain vocalization during electrical stimulation of the tail. The antinociceptive action was abolished by naloxone. Morphine (3 mg/kg) activated the self-stimulation response, whereas naloxone antagonized this action. The role of opiate receptors in self-stimulation effects and in central analgesia is discussed.Department of Pharmacology, I. P. Pavlov First Leningrad Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 11, pp. 569–572, November, 1979.     

Effect of morphine and naloxone on acupuncture analgesia in unrestrained rats

Experiments on unrestrained rats showed that electroacupuncture of an acupuncture point distinctly reduces the nociceptive response to electrical stimulation of the base of the tail. Morphine, in a subanalgesic dose (5 mg/kg), potentiated the analgesic effect of acupuncture. Naloxone, in a dose of 5 mg/kg, completely abolished acupuncture analgesia. The possible mechanisms of analgesia production by electroacupuncture are discussed.Department of Pharmacology, I. P. Pavlov First Leningrad Medical Institute. Course of Reflex Therapy, S. M. Kirov Leningrad Postgraduate Medical Institute. (Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 88, No. 11, pp. 566–569, November, 1979.     

Effect of morphine and naloxone,injected into pregnant rats on the adrenals and testes of the offspring

Laboratory of Genetic Basis of Neuroendocrine Regulation, Institute of Cytology and Genetics, Siberian Branch, Academy of Sciences of the USSR, Novosibirsk. National Institute of Clinical Laboratory Research, Budapest, Hungary. (Presented by Academician of the Academy of Medical Sciences of the USSR V. P. Kaznacheev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 1, pp. 58–60, January, 1992.     

Changes in sensomotor cortical peptide levels in the rat brain on the appearance of poststimulus paroxysmal discharges

Research Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 2, pp. 118–120, February, 1992.