Sedimentological features of various age river channel deposits on the example of the upper Czarna Hancza valley (Suwalskie Lakeland)

The aim of the research carried out in the upper Czarna Hańcza valley was to explore the characteristics of channel deposits from various ages and to evaluate their significance in the process of drawing conclusions about the fluvial environment. The deposits of the contemporary Czarna Hańcza channel were analysed; the channel itself is tortuous, locally meandering, with small meanders (with the curve radius of 30 to 70 metres). The deposits of the river with large-magnitude meanders were identified using the example of the Potasznia palaeomeanders, with the curve radius of 500 metres. The deposits of the braided sandur river, providing material for both types of younger fluvial deposits, were revealed in the exposures in Potasznia and Sobolewo. An analysis of the deposits' grain size was conducted using the sieve method, and the texture indicator was determined using the Folk and Ward method (1957). To draw conclusions about the environmental dynamics and the manner of transporting deposits on the basis of sedimentological features, the relationship between the average grain diameter - Mz (on the ϕ scale) and standard variation d₁ (sorting) was used, as well as one between the grain diameter - Mz and the first centile of the grain size distribution – C, which, along with larger ones, account, respectively, for 50% and 1 % of the deposit mass (Passega 1956, Passega Byramjee 1964, Mycielska-Dowgiałło 1995). In the relationship between the average grain diameter - Mz and the standard deviation - σ₁ pattern I was better visible in all the examined deposits, in which the thicker deposits were more poorly sorted. According to Mycielska-Dowgiałło (1995), it is a characteristic feature of a dynamie channel environment. Younger series are characterised by lesser differences in the average grain diameter, accompanied by larger variations in the sediment sorting and, at the same time, a poorer degree of sorting (individual channel types represent the lines with a similar ten dency, Mz-σ₁ but having a smaller channel gradient). Pattern II could be discerned only in the current facies deposits (which until naw has not been identified in the bottom deposits of Polish rivers), in which thicker deposits are better sorted. This is channel lag deposits. Also, in the C-M diagram, most of the points representing the examined deposits can be found in field I, comprising deposits transported in traction in an environment characterised by a high dynamie activity. In the case of contemporary channel deposits, the dependence of the deposition conditions on the channel gradient could be easily visible

7-Nitroindazole Enhances Amphetamine-Evoked Dopamine Release in Rat Striatum. An in Vivo Microdialysis and Voltammetric Study

The intracellular second messenger nitric oxide (NO) is implicated in a variety of physiological functions, including release and uptake of dopamine (DA). In the described study, in vivo microdialysis and differential pulse voltammetric techniques were used to determine the involvement of NO in release of DA and its metabolites (dihydroxyphenylalanine, DOPAC; homovanillic acid, HVA) in neostriatum of freely moving rats. While the NO donor molsidomine (30.0 mg/kg; MOLS) and neuronal NO synthase- (nNOS-) inhbitor 7-nitroindazole (10.0 mg/kg; 7-NI) had no effect on the basal in vivo microdialysate level of DA, 7-NI specifically enhanced D,L-amphetamine- (1.0 mg/kg i.p.; AMPH) evoked release of DA. Basal or AMPH effects on DOPAC and HVA levels were not influenced by MOLS or 7-NI. Findings indicate that nitrergic systems have an important role in mediating effects of AMPH on dopaminergic systems

A novel plasmid pIJB1 possessing a putative 2,4-dichlorophenoxyacetate degradative transposon Tn5530 in Burkholderia cepacia strain 2a

A 102-kb plasmid, pIJB1, was isolated from Burkholderia cepacia strain 2a, which is able to use 2,4-dichlorophenoxyacetate (2,4-D) as a sole carbon source, and a physical map of the plasmid has been established. It was observed that spontaneous loss of a 37-kb fragment of the plasmid after growth in nonselective medium occurred, generating a plasmid of diminished size, pIJB2. The deletion event is concomitant with the loss of the 2,4-D dissimilatory phenotype, indicating that at least some of the 2,4-D degradative genes are on the missing fragment. The missing fragment is flanked by two identical 4.3-kb insertion sequences (IS) and shows a typical composite transposon structure of 41-kb in size, designated Tn5530. The mutant plasmid pIJB2 possesses a single copy of the IS element

7-OH-DPAT, Unlike Quinpirole, Does Not Prime a Yawning Response in Rats

Repeated treatment in ontogeny with the dopamine (DA) D2/D3 receptor agonist quinpirole is associated with enhanced quinpirole-induced yawning and other behaviors such as vacuous chewing, vertical jumping, and antinociception. To determine if the reputedly DA D3 agonist (±)-2-(dipropylamino)-7-hydroxy-1,2,3,4-tetrahydronaphthalene (7-OH-DPAT) would prime for yawning in a manner analogous to that for quinpirole, rats were treated for the first 11 days after birth with an equimolar dose of either quinpirole or 7-OH-DPAT (195.4 nmol/kg/day) and tested for agonist-induced yawning in adulthood. While enhanced quinpirole-induced and 7-OH-DPAT-induced yawning was observed in quinpirole-primed rats, acute treatments with quinpirole and 7-OH-DPAT did not produce an enhanced yawing response in 7-OH-DPAT-\u27primed\u27 rats. Our findings indicate that 7-OH-DPAT, unlike quinpirole, does not prime for quinpirole- or 7-OH-DPAT-induced yawning in rats

Modulation of Central Dopamine Receptor Reactivity in the Rat, by Nitric Oxide Donors and Inhibitor: Behavioral Studies

Nitric acid has been implicated in a variety of physiological functions of the mammalian brain, and in a large number of its pathologies. Recently we have demonstrated that a nitric oxide donor (L-arginine) and a nitric-oxide-synthase-inhibitor (nitro-L-arginine-methyl-ester) modified the response of central al dopamine D 1 and D 3 receptors to some of their agonists. In the present study we demonstrate the modulatory effect of L-arginine, nitro-L-arginine-methyl-ester and molsidomine (another nitric oxide donor) on the reactivity of the central dopamine receptors to specific agonists and antagonists. The agonists tested were SKF-38393, 7-OH-DPAT and quinpirole, and the antagonists - SCH-23390 and haloperidol. They were evaluated in the rat by the following behavioral methods: locomotor activity, locomotor coordination, rearings and cataleptogenic activity (D 2 modulation); grooming time (D 1 activation); yawning (D 3 activation) and ethanol- and phenobarbital-sleeping-time parameters after SKF-38393 or quinpirole pretreatment. Our results suggest that nitro-L-arginine-methyl-ester is effective in modulating the reactivity of the central dopamine receptors D 2, D 1 and D 3, to their agonists and antagonists, and that it is much more effective than L-arginine in regulating the righting reflex after ethanol and phenobarbital, in both female and male mature rats

Locomotor Sensitization of Dopamine Receptors by Their Agonists Quinpirole and SKF-38393, During Maturation and Aging in Rats

Our laboratories have been investigating the reactivity of central dopamine D1 and D2/D3 receptors by their corresponding dopamine agonists (SKF-38393 and quinpirole), during development and aging in rats. By evaluating the number of oral movements (a parameter for D1 receptor activation after SKF-38393) and the number of yawns (as a parameter for D3 activation after quinpirole), we demonstrated that not only was there a dose-response activity for both drugs in the two parameters tested, but that the D3 activity was enhanced with the rats\u27 development and aging, due to life-long persisting D3 supersensitivity. In the present study we checked whether D2 and D1 receptors were also sensitized at old age, by measuring behavioral parameters characteristic to D2 (locomotor activity and rearings) and to D1 (grooming time). In the long-term study, male Wistar rats were challenged for 18 months with increasing doses of either SKF-38393, quinpirole or saline. At the age of 19 months they were given a single injection of either drug or saline. In the short-term study, male and female rats were given four single injections of either SKF-38393, quinpirole or saline, with one week intervals, and locomotor time and number of rearings recorded. Long-term quinpirole was found to induce supersensitivity of the D2 receptor complex, demonstrated by both enhanced locomotor time and rearing behavior, while long-term SKF-38393 treatment activated the D1 receptors, as evaluated by grooming time. Short-term quinpirole enhanced supersensitivity of the D2 receptors only in female rats, as assessed by increasing both locomotor time and rearing behavior, reiterating previous results on sex-dependent monoaminergic reactivity

Research into analgesic effect of ondansetron in persistent pain model in rats with central noradrenergic system lesion

Introduction. Many known substances affecting the serotoninergic system induce definite physiological effects, including those which are therapeutic. For instance, the enhanced serotoninergic transmission due to decreased functions of autoreceptors and increased inhibitory functions of postsynaptic 5-HT1A is associated with antidepressant effect. The central serotoninergic system takes part in the regulation of many bodily functions, such as sleep, wakefulness, blood pressure, pain perception or sexual behaviours. Moreover, it is involved in the pathogenesis of depression, anxiety, addictions, migraine and other headaches. In pain therapy, not only typical analgesics are used, but also substances without obvious analgesic effect, thus allowing potential pharmacological modulation of analgesic activity in the treatment of pain. Objective. The aim of the study was to determine whether a chemical lesion to the central noradrenergic system at an early stage of individual development alters reactivity of 5-HT3 receptors in adult rats. Materials and method. The study used newborn and adult Wistar rats aged 8–10 weeks. Behavioural tests (writhing test, formalin assay) were used to assess the analgesic action of ondansetron as a 5-HT3 receptor antagonist. Results. The analgesic effect of ondansetron (1.0 mg/kg b.w., i.p.) in the writhing test was weak and short. Pain intensity score after ondansetron injection (1.0 mg/kg b.w., i.p) was 2–3 points and did not differ significantly between the study groups. Conclusions. Damage to the central noradrenergic system at an early stage of individual development has no effect on the antinociceptive effects of the serotonin (5-HT3) receptor antagonist, ondansetron, in the persistent pain model