Intracellular dialysis and membrane voltage clamping were used to show that He-Ne laser irradiation of a pond snail neuron at a dose of 0.7 x 10(-4) J (power density 1.5 x 10(2) W/m2) increases the amplitude of the potential-dependent slow potassium current, while a dose of 0.7 x 10(-3) J decreases this current. Bupivacaine suppresses the potassium current. Combined application of laser irradiation at a dose of 0.7 x 10(-3) J increased the blocking effect of 10 microM bupivacaine on the slow potassium current, while an irradiation dose of 0.7 x 10(-4) J weakened the effect of bupivacaine.

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The pathogenesis of migraine is based on the aseptic inflammation of dura mater tissues surrounding the large cranial vessels, such as the superior sagittal sinus. This inflammation develops in conditions of antidromic activation of sensory terminals of the trigeminal nerve and is accompanied by changes in the responses of neurons in the spinal nucleus of the trigeminal nerve to electrical stimulation of the superior sagittal sinus. However, the characteristics of the responses of these neurons to this stimulation have received virtually no study. Experiments on anesthetized rats were performed with recording of the responses of 387 neurons in the spinal nucleus of the trigeminal nerve to electrical stimulation of the superior sagittal sinus. The results showed that the responses of neurons to this stimulation was biphasic, consisting of a short initial phase with a latent period of 7-19 (11.4 +/- 0.17) msec, followed by a longer-lived discharge with a latent period of 20-50 (34.2 +/- 0.8) msec. It is suggested that the first phase reflects orthodromic activation of perivascular A(delta) and C fibers of the trigeminal nerve, while the second phase is associated with activation of meningeal C fibers with low conduction velocities and/or secondary activation of the perivascular sensory endings of the trigeminal nerve by algogenic and vasoactive substances released from them during antidromic activation. These changes seen in animal experiments may serve as an indicator of the efficacy of antimigraine agents.

612.821.i/.3.014.46:547.95:547.943 and M. I. Titov KEY WORDS: aggression; defense; intraspecific behavior; met-enkephalin; leu-enkephalin.The role of enkephalins and their analogs in the regulation of mechanisms of memory, analgesia, certain motor acts, and autonomic reactions has been demonstrated recently [4,[6][7][8]. However, the spectra of their action on intraspecific (zoosocial) behavior have not been analyzed.The aim of the present investigation was to analyze the spectrum of action of met-and leu-enkephalins and of the tetrapeptide Tyr-D-AIa-GIy-Phe-NH2 on various forms of intraspecific behavior of isolated aggressive mice and to compare it with the analgesic activity of these peptides.Identification and analysis of effects of this sort are important in order to understand the role of endogenous peptides and their synthetic analogs in the regulation of complex forms of behavior. EXPERIMENTAL METHODExperiments were carried out on 30 male CC57W mice kept in single cages for 12 weeks. Free interaction of an aggressive isolant with a standard partner from the group was recorded by means of a special combination of Ethograph and EC 1022 computer [3]. The frequency and order of appearance of 25 different behavioral acts and postures of the isolated animal were recorded.All acts and postures were classified in motivation categories and coded on a binary code for computer analysis.The behavioral acts were subdivided into categories characterizing zoosocial behavior (intraspecific sociality), aggression, ambivalent (double motivational) behavior, defense, and individual behavior ( Table I). The degree of analgesia was estimated in points on the basis of behavioral criteria [i, 2]. Met-and leu-enkephalins and the tetrapeptide were injected intraperitoneally in a volume of 0.i ml/10 g body weight.Metenkephalin also was injected into the lateral ventricle in doses of 50 ~g. The effects were assessed 5 and 30 min after injection of the preparations.The significance of the results was estimated by means of Wilcoxon's nonparametric criterion for conjugate sets. EXPERIMENTAL RESULTSMet-enkephalin in a dose of 50 mg/kg increased the likelihood of an aggressive attack on the partner 5 min after systemic injection (Table i), reduced intraspecific sociality, potentiated ambivalent forms of behavior, and reduced the likelihood of individual forms of behavioroIn the above-mentioned doses, met-enkephalin did not cause analgesia, as assessed by behavioral criteria (n = 6, T A = O; P <0~ ~fter 30 min the frequency of overt aggressive acts was close to the control values, but threatening manifestations were increased, as also was vertical motor activity (standing up on the hind limbs).Leu-enkephalin, in a dose of 50 mg/kg, reduced intraspecific sociality after 5 min (Table I) and potentiated aggressive behavior.Unlike met-enkephalin, leu-enkephalin induced defensive behavior in the mice, which was not observed in the control.Leu-enkephalin depressed dynamic and intensified static (sitting) forms of individual behavior.After 3...

340Local anaesthetics, anti-arrythmic, analgesic, and psychotropic agents exert diverse membranotropic effects on a nerve cell. They increase (activate) or decrease (inhibit) ionic currents through voltage-gated sodium, calcium, and potassium channels; change the membrane surface charge in the vicinity of the ion channels; inactivate the channels or counteract their inactivation. Interactions of the pharmacological agents with channel gating structures result in alteration of the activation or inactivation kinetics. Membranotropic effects cause changes in membrane resting potential, synaptic potentials, and intercellular communications. Understanding the functioning mechanisms of neurons and possible ways of regulating their state pharmacologically makes the base of the concept of the cytopharmacological management of the cell functional state.

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