Search

The tetrapeptide tuftsin (Thr-Lys-Pro-Arg) injected intraperitoneally into cats altered the bioelectrical activity of sensory, motor, and limbicoreticular structures in the wakeful state, during two different phases of sleep, and also when the caudate nucleus was electrically stimulated. In wakefulness and during REM sleep, absolute values of the electroencephalographic power spectrum were increased in all the brain structures under study, while during slow-wave sleep they were increased in the sensorimotor cortical areas and decreased in the central medial thalamic nuclei and hippocampus. Tuftsin facilitated the genesis of slow waves in subcortical structures and the expression of theta waves in the hippocampus. It also increased the amplitude of evoked potentials and elongated spindles when the caudate nucleus was stimulated.

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.

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.

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.

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.

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.

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.

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.

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.