[Receptors of ionotropic mediators in snail neurons: the ionic nature and mechanisms of their functional regulation and topography]. / Retseptory ionotropnykh mediatorov v neironakh vinogradnoi ulitki: ionnaia priroda i mekhanizmy reguliatsii funktsii i topografii.

In the paper are described the responses of identified neurons to application of acetylcholine, glutamate, glycine, and gamma-aminobutyric acid. Were studied the ionic mechanisms of these responses and the effects of different agents (metabotropic neurotransmitters, peptides, vitamins, and lectins) on the functional properties and topography of the receptors of ionotropic neurotransmitters.

[The affinity lavage of the abdominal cavity in diffuse peritonitis with liquid sorbents based on cross-linked dextrans]. / Affinnyi lavazh briushnoi polosti pri razlitom peritonite zhidkimi sorbentami na osnove sshitykh dekstranov.

Experiments were conducted on 35 Wistar rats with generalized purulent peritonitis. Twenty-four hours after infection the authors introduced into the animals' abdominal cavity gels of cross-linked dextrans with immobilized polymixin (50 mg/g dry weight) and terrilithin (100 PE/g dry weight), as well as a combination of these sorbents with 24-hour exposure in a 5 ml volume. The object of the study was the detoxification effect. The authors revealed a phenomenon of agglutination of red cells of an ox or rat sensitized by plasma of sick animals in mixing with sephadex G-200 granules with polymixin W immobilized on them. The agglutination titers determined the activity of the sorbent taking part in lavage of the abdominal cavity. The study showed that cross-linked dextrans with immobilized polymixin B and terrilithin introduced into the abdominal cavity in peritonitis are capable of extracting substrates possessing affinity to them, the polymixin sorbent raises the quality of careful mechanical lavage. Combination of gels based on cross-linked dextrans with enzymatic and affinity functions in relation to toxins leads to detoxification and restoration of the disturbed biochemical values by 87%.

[Effect of vitamins B2 and B6 on the functional properties of cholinoreceptors in molluscan neurons]. / Vliianie vitaminov B2 i B6 na funktsional'nye svoistva kholinoretseptorov v neironakh molliuska.

It is found that vitamins B2 and B6 modified the form of the acetylcholine response in identified Helix pomatia neurons. This effect is mainly conditioned by a delay in desensitization.

[Mechanism of vitamin B6 regulation of acetylcholine-induced currents in mollusk neurons: pre- and postsynaptic effects]. / Mekhanizm reguliatsii vitaminom B6 atsetilkholinindutsiruemykh tokov v neironakh molliuska: pre- i postsinapticheskie éffekty.

Vitamin B6 has been studied for the mechanism of its effect on acetylcholine-induced sodium-potassium and chloride currents in E16 neuron of isolated brain of the snail Helix pomatia. The results indicate that the effect of vitamin B6 on acetylcholine-induced currents in postsynaptic neuron E16 is mediated via changes in gamma-aminobutyric acid (GABA) release from a presynaptic neuron and subsequent GABA-induced and cAMP-dependent processes in E16 neuron. It is suggested that effects of vitamin and antivitamin B6 on axons of a presynaptic neuron or neurons may be connected with regulation of GABA synthesis from glutamate catalyzed by the pyridoxal-phosphate-containing enzyme.

[Use of lectins for the study of carbohydrate determinants of cholinoreceptors of various subtypes in mollusk neurons]. / Ispol'zovanie lektinov dlia issledovanii uglevodnykh determinant kholinoretseptorov raznykh podtipov v neironakh molliuska.

Chemical nature of carbohydrate components in identified neurons of mollusc Helix pomatia influencing acetylcholine responses was investigated using different lectins (Con A, RCA, WGA and LPA). Differences between Con A-evoked changes in acetylcholine-induced chloride and sodium-potassium currents as well as differences in the time and temperature dependences of these changes showed various mechanisms of action of carbohydrate component with mannose residues on the function of acetylcholine receptors. The analysis of the time and temperature dependences of depressing effects of WGA and RCA on acetylcholine-induced currents permits supposing endocytosis of lectin-receptor complexes with N-acetyl-D-glucosamine residues.

[Effect of a catalytic subunit of cAMP-dependent protein kinase on acetylcholine-induced chloride currents in mollusk neurons]. / Vliianie kataliticheskoi sub"edinitsy tsAMP-zavisimoi proteinkinazy na atsetilkholinindutsiruemye khlornye tochki v neironakh molliuska.

It is shown that the amplitude of ACh-induced chloride currents decreases with introduction of cAMP in dialyzed neurons of Helix pomatia, the rate of desensitization of the acetylcholine receptors (AChR) being insignificantly changed. Introduction of an active catalytic subunit (c.s.) of cAMP-dependent protein kinase (cAMP-PK) mimics this effect. It is supposed that the influence of cAMP on the functional properties of the AChR is mediated by the activation of cAMP-PK and further phosphorylation of the AChR by the catalytic subunits of this protein kinase.

[Features of the chlorine-dependent effect of acetylcholine and neutral amino acids on neurons of the Achatina snail]. / Osobennosti khlorzavisimogo vliianiia atsetilkholina i neitralnykh aminokislot na neirony ulitki-akhatiny.

Responses of neurons in cerebral ganglia of an African giant snail (Achatina fulica) to acetylcholine (ACh), gamma-aminobutyric acid (GABA) and glycine (Gly) were investigated. Cl-dependent currents induced by these mediators in neurons of one and a half month old snail sibs were inhibited by dibutyryl-cAMP and strychnine. Inhibition of ACh-responses by 10(-8) mol/l GABA was mimicked by applications of dibutyryl-cAMP and isobutylmethylxanthine. GABA- and Gly-responses exhibited complete cross-desensitization, but this effect was absent for ACh and GABA (or Gly). On the basis of pharmacological dependences of GABA- and Gly-responses it is suggested that these amino acids act on the same receptor-channel complex in neurons of young snails. ACh-, GABA- and Gly-induced chloride currents were independent in neurons of four years old snails.

[Tocopherol modulation of acetylcholine-induced current in mollusk neurons]. / Moduliatsiia tokoferolom atsetilkholinindutsiruemogo toka v neironakh molliuska.

It is shown that vitamin E (tocopherol) and arachidonic acid are antagonists at the cellular level in regulation of Ca-calmodulin-dependent acetylcholine-induced current in molluscan neurons.

[Oxytocin modulation of the functional properties of 3 types of cholinoreceptors in mollusk neurons]. / Moduliatsiia oksitotsinom funktsional'nykh svoistv trekh tipov kholinoretseptorov v neironakh molliuska.

It was found that 10(-8) mol/l oxytocin (OT) application exerted effects on functional properties of three types of acetylcholine (ACh) receptors in neurons identified in the ganglia of Helix pomatia under voltage clamp conditions. OT depressed ACh-induced sodium-potassium-calcium current in neuron RB3 without a shift of the reversion potential. The data obtained show that there are two types (subtypes) of ACh receptors connected with chloride channels. OT decreased the ACh-induced chloride current in neuron F4 and enhanced the ACh-induced chloride current and desensitization of ACh receptors in neurons D5, F86. Effects of OT and serotonin applications were reversible but not additional. Effects of OT injection and OT application were independent. The present results suggest that cyclic AMP may be the second messenger mediating the OT-induced modulation of functional properties of three types of ACh receptors.

[The effect of calcium ions on the acetylcholine-induced current in mollusk neurons]. / Vliianie ionov kal'tsiia na atsetilkholin-indutsiruemyi tok v neironakh molliuska.

It has been found that cyclic adenosine monophosphate and intracellular calcium ions produced an antagonistic effect on acetylcholine-induced current in LP11 neuron of the snail Helix pomatia. It is shown that the activation of calmodulin by calcium ions plays a significant role in enhancing action of intracellular calcium ions on the acetylcholine-induced current in this neuron.

[Serotonin modulation of acetylcholine-induced currents in mollusk neurons as dependent on cyclic guanosine monophosphate]. / Moduliatsiia serotoninom atsetilkholin-indutsiruemykh tokov v neironakh molliuska, zavisimaia ot tsiklicheskogo guanozinmonofosfata.

It was found that a serotonin-induced decrease of the acetylcholine-induced chloride current in a group of right parietal ganglion neurons of the snail Helix pomatia was mimicked neither by dibutyryl cAMP nor by isobutyl methylxanthine. In contrast it was mimicked by the extracellular application of sodium nitroprusside as a guanylate cyclase activator, and by intracellular injection of cyclic guanosine monophosphate.

[The effect of ultrasound on the functional state of the nicotinic cholinoreceptors in mollusk neurons]. / Vliianie ul'trazvuka na funktsional'noe sostoianie nikotinovykh kholinoretseptorov neironov molliuska.

It was found that ultrasound (0.5 W/cm2, 2.64 MHz) produced a blocking effect on acetylcholine (ACh)-induced chloride current in Helix pomatia neurons. Atropine blocked the chloride channels opened by ACh and did not prevent from the blocking effect of ultrasound. Ultrasound became effectless after binding of ACh molecules to the recognizing centre of nicotinic acetylcholine receptors.

[Subsynaptic modulation of chemical stimulation transmission by metacerebral neurons in the buccal ganglia of mollusks]. / Subsinapticheskaia moduliatsiia metatserebral'nymi neironami khimicheskoi peredachi vozbuzhdeniia v bukkal'nom ganglii molliuska.

Stimulation of giant metacerebral serotonin-containing cell LMc1 in Helix pomatia was studied for its effect on responses of buccal cells LBc2 and LBc3 to stimulation of buccal nerves. Stimulation of cell LMc1 modulated those responses either increasing or decreasing them. Results of applications of serotonin, dibutyryl-cAMP, methysergide, d-tubocurarine and acetylcholine on cells LBc2 and LBc3 suggest that the modulation of responses of buccal cells LBc2 and LBc3 to buccal nerves stimulation by cell LMc1 was subsynaptic.

[Potentiating and blocking action of cyclic adenosine monophosphate and lithium ions on mollusk neuronal responses caused by acetylcholine and gamma-aminobutyric acid]. / Potentsiruiushchee i blokiruiushchee deistvie tsiklicheskogo adenozinmonofosfata i ionov litiia na otvety neironov molliuska, vyzvannye atsetilkholinom i gamma-aminomaslianoi kislotoi.

It was found that cyclic adenosine monophosphate and lithium ions produced blocking effects on acetylcholine-induced currents carried by sodium, potassium and calcium ions in neurons of Helix pomatia. Lithium ions produced biphasic actions on ACh-induced and gamma-aminobutyric acid-induced chloride currents.

[Bimodal effect of serotonin on glutamate-induced ionic currents in Helix pomatia neurons]. / Bimodal'noe deistvie serotonina na glutamat-indutsiruemye ionnye toki v neironakh vinogradnoi ulitki.

Bimodal effect of serotonin on glutamate-induced ionic currents was found in experiments on Helix pomatia neurons under voltage clamp conditions. The results of a 1 min exposure to theophylline, dibutyryl-cAMP or imidazole have shown the participation of intracellular processes connected with adenosine 3':5'-cyclic monophosphate and calcium ions in this bimodal effect of serotonin.

[Serotonin modulation of glycine-induced ionic currents in mollusk neurons]. / Moduliatsiia serotoninom glitsin-indutsiruemykh ionnykh tokov v neironakh molliuska.

It was found that serotonin decreases glycine-induced response in Helix pomatia neurons. The Ca2+ injection into the cell increased glycine-induced currents, i.e. the type of modulating serotonin action on the glycine-induced response was changed. Effects of theophylline, dibutyryl-cAMP and imidazole on glycine-induced currents indicated that the cyclase system of the nerve cell was involved in the bimodal action of serotonin of glycine-induced ionic currents.