Effect of β-phenylethylamine on dopaminergic systems of the rat brain

The time course of changes in the dopamine concentration in dopaminergic neurons of the nigro-neostriatal and mesolimbic systems of the rat brain during 1 h after intraperitoneal injection of -phenylethylamine (100 mg/kg) was studied by quantitative fluorescence-histochemical analysis. The results showed that -phenylethylamine causes a marked fall in the dopamine level in neurons of dopaminergic systems of the brain. The dopamine level in the bodies of dopaminergic neurons changes more than in their axon terminals. The fall in the dopamine concentration in the dopaminergic systems of the brain during the first hour is irregular in character: in the terminals between 10 and 30 min and in the bodies between 30 and 45 min there is actually a temporary increase in the dopamine concentration. The rise in the dopamine concentration in the terminals coincides with a sharp fall in the dopamine level in the neuron bodies, and conversely, the fall in the dopamine concentration in the terminals after 30 min is accompanied by some increase in the dopamine concentration in the neuron bodies. The results suggest that the increase in motor activity described in the literature in animals after injection of -phenylethylamine is connected with its action on catecholaminergic, especially dopaminergic, brain systems.Institute of Biophysics, Academy of Sciences of the USSR, Pushchino-on-Oka. Translated from Neirofiziologiya, Vol. 11, No. 6, pp. 578–584, November–December, 1979.     

Raoultella planticola, a new strain degrading 2,4,5-trichlorophenoxyacetic acid

A new strain that degrades the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was isolated from soil, which was exposed to factors related to the petrochemical industry. According to its physiological, biochemical, cultural, and morphological traits, together with the sequence of the 16S rRNA gene, the strain was identified as Raoultella planticola 33-4ch. The strain could consume 2,4,5-T as a sole source of carbon and energy. The amount of 2,4,5-T in the culture medium decreased by 51% after five days of incubation. Raoultella planticola 33-4ch consumes 2,4,5-T to produce 4-chlorophenoxyacetic, phenoxyacetic, and 3-methyl-2,6-dioxo-4-hexenoic acids.     

Evolution and Comparative Genomics of the pSM22 Plasmid of the IncF/MOBF12 Group

Molecular Biology - A new plasmid, pSM22, was isolated from Serratia marcescens and sequenced. Its 43 190-bp sequence with an average GC-content of 58% contains 31 open reading frames (ORFs) which...     

High temporal resolution of amino acid levels in rat nucleus accumbens during operant ethanol self-administration: involvement of elevated glycine in anticipation

Capillary electrophoresis coupled with laser-induced fluorescence detection (CE-LIF) provides 15-s temporal resolution of amino acid levels in microdialysate, which, for the first time, allows almost real time measurement of changes during episodes of behavior. We trained Sprague-Dawley rats to self-administer either 10% ethanol-containing gelatin or non-alcoholic gelatin in a typical operant chamber. After rats reached stable daily levels of responding, microdialysis probes were inserted into nucleus accumbens and samples were collected before, during and after operant sessions with on-line analysis via CE-LIF. During the first 15 min of the operant session, there was a significant increase in taurine that correlated with the amount of ethanol consumed ( R ² = 0.81) but no change in rats responding for plain gel. There were large, consistent increases in glycine in both the ethanol and plain gel groups which correlated with the amount of gel consumed. A smaller increase was observed in rats with free non-operant access to plain gel compared to the increase seen with the same amount of gel consumed under operant conditions. When rats were given a time out after each delivery of gel in the operant protocol, the greatest increase of glycine was obtained with the longest time out period. Thus, increases in glycine in nucleus accumbens appear to be related to anticipation of reinforcement.     

EEG markers of upright posture in healthy individuals

The EEG spectral-coherence parameters were analyzed in 10 healthy individuals (mean age, 22 ± 0.67 years) at different steps of verticalization, from the lying position to the sitting and standing positions. The maximal changes in all EEG parameters were revealed when the upright posture was maintained in the absence of visual control. Under these conditions, a power increase for the fast EEG components (the ??- and ??-bands) was observed, as was an additional increase when the conditions of maintaining the upright posture were complicated. According to the results of the EEG??s coherent analysis, human verticalization revealed a specific increase for most of the EEG rhythm ranges in the right hemisphere, especially in the frontocentral and occipitoparietal regions, as well as for the interhemispheric coherences for these leads reflecting the involvement of both cortical and subcortical structures in these processes. When the posture maintenance conditions were complicated, an additional coherence increase in the fast EEG bands (the ??-rhythm) was observed in the frontal cortical regions, which was evidence of the increase in the executive functions under these conditions.     

Integrating role of voluntary postural control recovery during rehabilitation of patients with traumatic brain injury

Results of complex clinical, stabilographic and electroencephalographic (EEG) examination of 20 patients (28 +/- 6.9 years) suffered a severe traumatic brain injury (STBI) are presented. The examination was carried out in early terms after the STBI before and after a course of stabilographic training (ST) with a visual feedback as compared to a group of 18 healthy volunteers (26 +/- 5.8 years). The 4- to 6-week course of ST consisted of 8-15 sessions. Before the course, the patients experienced problems in different kinds of activity, maximum in the motor sphere. The EEG study revealed a decrease in the power and coherence of the alpha rhythm and an increase in the power of the slow spectral bands (delta). The ST restored not only the postural control of patients, but also reduced the defects in other spheres. The EEG study showed an increase in the alpha-rhythm power maximum in the occipital-parietal areas and a tendency to normalization of its regional specificity. In all examined patients, the interhemispheric coherence increased for different EEG-rhythms, especially of the alpha-band, in the central and parietal brain areas. The described EEG changes can be a marker of the integrating role of postural control and an important stage in restoration of integrative brain activity in early terms after the STBI accompanied by improvement of damaged functions.     

Chromosome numbers and meiotic analysis in the pre-breeding of <Emphasis Type="BoldItalic">Brachiaria decumbens</Emphasis> (Poaceae)

A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them, 15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions.