Cholinoreceptors of early (preneural) sea urchin embryos.

Agonists of nicotinic cholinoreceptors (n-AChR) and 1-acetyl-4-methylpiperazine (100 microM) had no effect on early embryogenesis in sea urchins, while in the presence of phorbol-12-myristate-13-acetate (PMA) and various other protein kinase C activators, these agents induced rapid lysis of oocytes or early embryos, as a result of calcium shock. Many n-AChR ligands which do not penetrate into the cytoplasm (not being antagonists of muscarinic cholinoreceptors) protected against this cytotoxic effect. In the presence of PMA, acetylcholine and carbachol had actions which were much weaker than those of nicotine, while muscarine was completely inactive in these conditions. Thus, the surfaces of sea urchin oocytes and early embryos bear receptor structures, presumably n-AChR, which are functionally linked with second messengers which are endogenous protein kinase C activators.

[Effects of delta sleep-inducing peptide on the intercentral integration during experimental epilepsy]. / Vliianie peptida del'ta-sna na mezhtsentral'nuiu integratsiiu v usloviiakh éksperimental'noi épilepsii.

In free behavior experiments on cats it has been shown, that the intraperitoneal injection of delta-sleep-inducing peptide (100 mg/kg) may change organization of the pathology integration-epileptic discharges did not spread all the structures simultaneously. The slow-waves were registered in central medium of the thalamus and nucl. caudati. The epileptic discharges were registered first in visual and auditory cortex, hippocampus. After that they were observed in the motor cortex, nucl. caudati and centrum medianum of the thalamus.

Conditioned motor reactions in free-moving elasmobranchs and bony fishes.

Food-getting conditioned motor reflexes to light and darkness discrimination were developed in elasmobranchs (the sharks Scyllium canicula and Galleus canis) and bony fishes (Mugil capitocum). Several distinctions in ecological and conditioned motor behavior were observed in sharks with low and high degrees of organization. There were significant differences between elasmobranchs and bony fishes in ecological and food-getting behavior and in conditioned reflex reactions. The nervous activity of elasmobranchs is characterized by a lower and more primitive degree of organization, compared to bony fishes.

[New date on biogenic amines of developming sea urchin embryos]. / Novye dannye o biogennykh monoaminakh razvivaiushchikhsia émbrionov morskikh ezhei.

Using two fluorimetric techniques, identification and assay of indolylalkylamines have been made in sea urchin eggs and embryos. It was shown that serotonin-like substance of embryonic and adult specimens is not usually homogeneous and consists at least of two components, the main of them being presented by tryptamine or one of its derivatives with the replaced group at amino nitrogen. Serotonin is also present at all the developmental stages investigated although its concentrations are significantly lower. It is suggested that these substances are involved into regulatory processes during early embryogenesis.

[Visual projections into the telencephalon and diencephalon of the teleost fish Serranus scriba (electrophysiologic study)]. / Zritel'nye proektsii v konechnom i promezhutochnom mozgu kostistoi ryby Serranus scriba (élektrofiziologicheskoe issledovanie).

In acute experiments on Serranus scriba, two discrete foci of visual activity in the telencephalon were shown--in the dorsal pallium and in the central telencephalic area. The latency of focal potentials evoked by optic tectum stimulation was at least 2 msec shorter than that of the responses elicited by optic nerve stimulation. In the region of nucleus rotundus and some other thalamo-pretectal structures, focal potentials and single unit reactions to both types of stimulation were registered. Responses to optic tectum stimulation in nucleus pretectalis exhibited the shortest latency. It is suggested that visual impulses to the central telencephalic area are relayed consequently in the optic tectum and probably in more than one thalamo-pretectal nucleus.

[Free amino acids in the central nervous system of skates (Batomorpha)]. / Svobodnye aminokisloty v tsentral'noi nervnoi sisteme skatov (Batomorpha)

The distribution of free amino acids in strongly and weakly electric fishes (skates and rays) varies in relation to species, brain region and functional peculiarities. In comparison to the weakly electric fishes (Raja clavata and Myliobatis aquila) a number of brain regions of the strongly electric species (Torpedo marmorata and T. ocellata) show considerably higher concentrations of arginine, glycine and tyrosine, and lower concentrations of aspartic acid. The electric organ of the strongly electric fishes was characterized by the lack of tyrosine and glycine, by traces of GABA, and by considerably higher concentrations of alanine, serine, cysteine, and histidine than in the brain of the same species. The electromotor center Lobus electricus of the stronlgy electric fishes, in contrast to other brain regions, shows exceptionally high concentrations of tyrosine and alanine. In comparison to the mammalian brain, levels of brain alanine, glycine, cysteine and cystine are higher in the four fish species studied. The results are discussed in relation to the morphophysiological organization of the fish central nervous system and of the mechanisms of electrogenesis.

[Effect of monoamines, heat shock and other factors on the binding of several neuropharmacologic preparations by sea urchin embryos]. / Vliianie monoaminov, teplovogo shoka i drugikh faktorov na sviazyvanie nekotorykh meirofarmakologicheskikh preparatov émbrionami morskikh ezhei

Early embryos of the sea urchins Arbacia lixula and Paracentrotus lividus being subjected to an osmotic or heat shock (10 min at 70 degrees C or higher) do not longer bind cytotoxic pharmaca and do not affect the sensitivity of normal indicator embryos to these drugs. After exposure for 10 min at 40 degrees C, the binding of neuropharmaca by embryos is not affected, although their ability to protect indicator embryos from the action of these neuropharmaca is inhibited 4--5 times. Serotonin and adrenaline inhibit the binding of neuropharmaca by 10--20%, while meterazine, noveryl and an amphetamine derivative--IEM-567--inhibit it by 50--60%. Antimycin A, rotenone and mercuric chloride do not affect the binding of neuropharmaca by sea urchin embryos.

[Subcellular distribution of arginase and gamma-guanidino-butyrate-ureohydrolase in brain sections, neurons and glia]. / Subkletochnoe raspredelenie arginazy i gamma-guanidinbutirat-ureogidrolazy v otdelakh mozda, v neironakh i glii

Distribution of arginase and gamma-guanidine-butyrate-ureohydrolase in seven brain sections is studied. Specific activity of arginase in brain sections is 0.063-0.117 and of gamma-guanidine-butyrate-ureohydrolase -- 0.042-0.050 mcmoles of urea per 1 mg of protein for 30 min. Cortex and cerebellum neurons have the same arginase activity (0.12 mcmole/mg). Specific arginase activity in glial cerebellum cells is 3 times as much as in cortex glial cells (0.20 and 0.07 mcmole/mg respectively). The activity of gamma-guanidine-butyrate-ureohydrolase in glial cell is higher than in neurons. Subcellular distribution of both enzymes is studied in those brain sections where their activity is maximal. In cerebellum both enzymes were tested, in cortex -- gamma-guanidine-butyrate-ureohydrolase, in thalamus -- arginase. The highest specific arginase activity is found in cytoplasmic, microsomic and synaptosomic fractions. Gamma-Guanidine-butyrate-ureohydrolase is concentrated in cytoplasmic and synaptosomic fractions. Possible correlation of gamma-aminobutyric acid metabolism and participation of brain arginase in regulation of protein biosynthesis are discussed.

[Patterns in the binding of cytotoxic neuropharmacologic preparations by early sea urchin embryos]. / Zakonomernosti sviazyvaniia tsitotoksicheskikh neirofarmakologicheskikh preparatov rannimi émbrionami morskikh ezheA

Early embryos of Arbacia lixula, Paracentrotus lividus and Sphaerechinus granularis intensively bind cytotoxic neuropharmacological drugs, such as antiserotonine indole derivatives, cholinolytics and tricyclic antidepressants. The binding intensity decreases markedly upon quaternization of the drugs. Quantitative analysis indicates that: a)with respect to the drugs, the suspension of living embryos may be described as a single adsorbing system following the Langmuir equation; b) at least two independent binding pools exist in embryos; c) the magnitude of cytotoxic effect of a given drug is not proportional to its binding.

[Compensatory irradiation of excitation following partial deafferentation of the midbrain tectum of Serranus scriba]. / O kompensatornoi irradiatsii vozbuzhdeniia pri chastichnoi deafferentatsii kryshi srednego mozga Serranus scriba

The unit activity studies in the fish (Serranus scriba) tectum opticum showed that, after surgical isolation of a retinal segment, there was a slowing of spontaneous unit activity in the partially deafferented portion of the projection area, whereas the firing rate of responses to illumination of the remaining retina increased. Changes in information processes, latencies, and other response characteristics indicate that deafferented neurons could be activated as a result of intratectal spread of excitation.