Biomedical subjects

K Wiśniewski

Publications and source records attributed to K Wiśniewski.

At least 19 recordsLinked to original sources

PubMed2005

The influence of NMDA, a potent agonist of glutamate receptor, on behavioral activity of rats with experimental hyperammonemia evoked by liver failure.

The study was designed to investigate the effects of NMDA receptor agonist on the behavioral activity in rats with experimental hyperammonemia. The experiments were performed on adult male Wistar rats. Experimental hyperammonemia was induced by intraperitoneal injections of tioacetamide (TAA, 200 mg/kg) for three consecutive days. Rats treated with saline (0.9%) served as control. Stimulation of the NMDA glutamatergic receptor was evoked by ip. injection of agonist N-methyl-D-aspartate acid (NMDA) in a dose of 30 mg/kg thirty minutes before experiments. Memory motivated affectively was evaluated in the passive avoidance responses. The speculative influence of the treatment on anxiety and motor activity was tested in elevated plus-maze and in open field respectively. To show change of NMDA receptor function after various doses of agonist, the seizures evoked by N-methyl-D-aspartate acid was carried out. This experiment showed that with rise of dose of NMDA time to appear of convulsions was contracted in rats with hyperammonemia as well as in control rats. Dose of NMDA caused convulsions was three times as less in rats with hyperammonemia than dose in control. Time of duration of convulsions was proportional to applied dose of NMDA and it lengthened with rise of agonist's dose in both groups of studied animals. Furthermore, we observed that NMDA increased motor activity of control rats in open field test, but not in rats with hyperammonemia (treated tioacetamide). Hyperammonemia did not have significant influence on motor activity and on a passive avoidance latency. The NMDA given in control and in hyperammonemia, increased acquisition, consolidation and recall of a passive avoidance responses. Moreover, NMDA had anxiogenic-like profile in elevated plus-maze. In rats with hyperammonemia NMDA had no influence on locomotor activity but it significantly increased memory in a passive avoidance responses. Furthermore, we observed that reactivity of NMDA glutamate receptor in rats with hyperammonemia was higher than in control rats.

Animals↗

PubMed2004

Nuclear stopping from 0.09A to 1.93A GeV and its correlation to flow.

We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV. For the heaviest system, Au+Au, we observe a plateau of maximal stopping extending from about 0.2A to 0.8A GeV with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow.

Journal Article↗

PubMed2004

Azimuthal dependence of collective expansion for symmetric heavy-ion collisions.

Detailed studies of the azimuthal dependence of the mean fragment and flow energies in the Au+Au and Xe+CsI systems are reported as a function of incident energy and centrality. Comparisons between data and model calculations show that the flow energy values along different azimuthal directions could be viewed as snapshots of the fireball expansion with different exposure times. For the same number of participating nucleons more transversally elongated participant shapes from the heavier system produce less collective transverse energy. Good agreement with Boltzmann-Uehling-Uhlenbeck calculations is obtained for a soft nuclear equation of state.

Journal Article↗

PubMed2003

The role of ionotropic receptors of glutaminic acid in cardiovascular system. A. The influence of ionotropic receptor NMDA agonist - 1R,3R-ACPD and antagonist - DL-AP7 on the systemic pressure in rats.

The aim of our study was to estimate the involvement of the peripheral N-methyl-D-aspartate receptors in regulation of cardiovascular function. For this purpose we examined the effects of intravenous injection of the agonists - NMDA (0.025; 0.05 and 1.0 mg/kg iv) and 1R-3R-ACPD (0.025; 0.05 and 1.0 mg/kg iv) - and antagonist of NMDA receptors DL-AP7 (0.02; 0.07 and 0.2 mg/kg iv). To determine if the effects of NMDA come from central or peripheral action we observed the effect during blockade of autonomic ganglion by using the nicotinic receptor antagonist - chlorisondamine (1.25 mg/kg iv). Administration of NMDA in three doses evoked slight hypotension after injection of the medium dose, 0.05 mg/kg. In the condition of pretreatment with 1.25 mg/kg chlorisondamine the hypotensive effect of NMDA was markedly reduced, what might suggest that NMDA-induced hypotension raised from the action within the brain. The competetive NMDA receptor antagonist DL-AP7 slightly increased the blood pressure. None of the injected drug had an influence on the heart rate in our in vivo study. It is concluded that the peripherally localized NMDA receptors may take a part in regulation of cardiovascular system, since their stimulation or blockade evoked the changes of systemic pressure.

2-Amino-5-phosphonovalerate↗

PubMed2001

Baclofen prevents hypoxia-induced consolidation impairment for passive avoidance in rats.

We investigated the effects of baclofen, a selective GABA-B receptor agonist, on certain behaviours in rats after short-term hypoxia, as a model of experimentally induced amnesia. Baclofen given intraperitoneally (i.p.) in a dose of 0.25 mg kg(-1) increased the number of crossings and bar approaches in the open field, but was ineffective in the passive avoidance tests; it also shortened the time spent in open arms and reduced the number of open arms entries in an elevated 'plus' maze, being a measure of anxiety. Hypoxia (2% O2, 98% N2) within 4 min profoundly impaired locomotor activity, consolidation and retrieval of conditioned responses, and exhibited a proaxiogenic effect in the elevated 'plus' maze in rats--it reduced the time spent in open arms and the number of entries to closed and open arms. Baclofen's effect on locomotor and exploratory activity was substantially impaired after hypoxia, i.e. rats exhibited a significant reduction in those activities. This agonist of GABA-B receptor used before hypoxia significantly improved consolidation, but had no effect on retrieval. In the elevated 'plus' maze rats pre-treated with baclofen and then subjected to hypoxia prolonged the time spent in open arms, reduced the time spent in closed arms, and increased the number of entries to the arms, i.e. exhibited anxiolytic effect. We conclude, therefore, that baclofen improved consolidation of passive avoidance in rats undergoing hypoxia.

Amnesia↗

PubMed2001

Genotype-dependent proteolytic response of spring wheat to water deficiency.

Changes in proteolytic activities in response to water deficiency have been investigated in ten genotypes of spring wheat (Triticum aestivum L.) differing in response to water deficit stress and ability to acclimate. To determine subcellular localization and the type of proteases, mesophyll protoplasts isolated from wheat leaves were purified. Proteolytic activities were assayed using azocasein in the case of vacuolar proteinases at pH 5.0 and 125I-lysozyme in the case of extravacuolar ATP-dependent proteinases at pH 8.2. ATP-dependent proteolytic activity was found to be confined to the extravacuolar fraction while the azocaseinolytic activity to vacuoles. Dehydration increased vacuolar azocaseinolytic activity at both stages of plant development (shooting and heading), but the increase was significantly lower in more tolerant genotypes. The extravacuolar energy-dependent 125I-lysozyme degradation was low at the shooting stage but it was higher in the genotypes with a greater critical water saturation deficit. At the heading phase in the non-acclimated flag leaves ATP-dependent 125I-lysozyme degradation decreased in a genotype-dependent manner, but was enhanced upon acclimation to the same extent irrespective to the genotype ability to acquire dehydration tolerance during acclimation. The results presented indicate that both pathways of protein degradation are interlinked upon dehydration and are genotype dependent.

Adaptation, Physiological↗

PubMed2001

6-Hydroxydopamine infusions into the structures of mesolimbic dopaminergic system alter the memory enhancing effect of CK-8US and caerulein in rats.

The influence of bilateral destruction of dopaminergic endings in the anterior and in the posterior part of nucleus accumbens (NAS) and in the nucleus septi lateralis (NSL), by 6-hydroxydopamine (6-OHDA) infusions, on the facilitatory effect of cholecystokinin-unsulfated octapeptide (CCK-8US) and caerulein (CER) on memory motivated affectively was investigated in male Wistar rats. CCK-8US and CER were given s.c. at the doses of 10 microg/kg and 0.5 microg/kg respectively, immediately after a single learning trial in a passive avoidance situation, ten days after bilateral 6-OHDA lesions (desipramine pre-treatment; 25 mg/kg, i.p.) of these structures. Bilateral 6-OHDA lesions to the anterior and to the posterior part of NAS totally abolished and significantly attenuated, respective, the facilitatory effect of CCK-8US and CER on retention of a passive avoidance behaviour evaluated 24 h later, while bilateral lesions to NSL did not have any influence on it. Moreover, neither, destruction of dopaminergic endings in lesioned structures, nor application of CCK-8US and CER changed the spontaneous psychomotor activity of rats estimated in an "open field" test. These results may indicate that dopaminergic projection to the anterior part of NAS is mainly responsible for the facilitatory effect of CCK-8US and CER on memory motivated affectively.

Animals↗

PubMed2000

Behavioural activity of (S)-3,5-DHPG, a selective agonist of group I metabotropic glutamate receptors.

The influence of intracerebroventricular (i.c.v.) injections of (S)-3,5-dihydroxyphenyl-glycine (S)-3,5-DHPG, a selective agonist of group I metabotropic glutamate receptors (mGluRs), on the activity of the central nervous system was examined in male rats. (S)-3,5-DHPG at doses of 25, 50 and 100 nmol significantly attenuated crossings of squares and rearings, but not bar approaches, in an 'open field' test and failed to change apomorphine-induced stereotypy. (S)-3,5-DHPG at the above doses, given immediately after the learning trial, significantly facilitated the consolidation process in a passive avoidance situation, but given before the learning trial and before the retention testing did not have any influence on acquisition and retrieval processes, respectively. Moreover, (S)-3,5-DHPG did not influence recognition memory evaluated in an object recognition test. These results may suggest that activation of group I mGluRs takes part in the consolidation process in affectively-motivated memory, but is probably not necessary for processing of recognition memory, and that (S)-3,5-DHPG memory facilitation seems to be independent of glutamatergic and dopaminergic interaction.

Animals↗

PubMed1999

The synthesis of a new class of oxytocin antagonists.

The synthesis of a new class of oxytocin antagonists, with significantly modified C-terminal part, is described. The chemistry of the Mitsunobu reaction was applied to obtain the key derivatives. In spite of the extensive modifications of previously described compound F792, the peptides retain biological activity as oxytocin antagonists.

Animals↗

PubMed1999

Bilateral transections of temporo-entorhinal connections attenuate vasopressin improvement of memory in rats.

It has been found in our laboratory that the positive influence of vasopressin (AVP) on memory processes is mediated by excitatory amino acids, since it was abolished by NMDA receptor antagonists. The purpose of the present study was to investigate whether bilateral transections of glutamatergic temporo-entorhinal connections may have an influence on the facilitatory effect of AVP on retrieval process of a passive avoidance behaviour. The bilateral transections of temporo-entorhinal connections were made in male Wistar rats 10 days before testing of the influence of intracerebroventricular AVP (1 microgram per rat) injection on memory, evaluated in a passive avoidance task. Although AVP significantly facilitated the retrieval process both in sham-operated and in lesioned groups of rats, bilateral disruption of temporo-entorhinal connections significantly attenuated the facilitatory effect of AVP on the retrieval process. Moreover, bilateral transections of temporo-entorhinal connections failed to affect motor activity, such as crossings of squares, without an influence on rearings and bar approaches evaluated in an open field test. These results may suggest that in the facilitatory effect of AVP on the retrieval process is involved a reciprocal glutamatergic connection between the lateral entorhinal cortex and the temporal cortex.

Animals↗

PubMed1999

Dopaminergic projection to the central amygdala mediates the facilitatory effect of CCK-8US and caerulein on memory in rats.

The involvement of dopaminergic projection to the central amygdala in the facilitatory effect of cholecystokinin unsulphated octapeptide (CCK-8US) and caerulein (CER) on memory motivated affectively was investigated in male rats. CCK-8US and CER were administered subcutaneously at the doses of 10 micrograms kg-1and 0.5 microgram kg-1, respectively, immediately after a single learning trial in a passive avoidance situation, after bilateral 6-OHDA lesions to the central amygdala. Bilateral 6-OHDA lesions to the central amygdala totally abolished the facilitatory effect of CCK-8US and CER on retention of passive avoidance behaviour evaluated 24 h after the learning trial. These results may indicate that the facilitatory effect of CCK-8US and CER on memory motivated affectively is mediated by dopaminergic projection from ventral tegmental area to the central amygdala.

Amygdala↗

PubMed1999

Baclofen and AII 3-7 on learning and memory processes in rats chronically treated with ethanol.

The aim of this study was to determine the possible influence of baclofen, an agonist of the GABA(B) receptor on behavioral activity (recall, acquisition of conditioned reflexes) of angiotensin II fragment 3-7 (AII 3-7) in rats chronically treated with ethanol. Long-term (9 weeks) ethanol intoxication profoundly impaired learning and memory processes in all tests used. The GABA(B) receptor agonist baclofen (0.75 mg/kg i.p.) did not influence exploratory and motor activity in the control rats, but we observed a tendency (without significance) to decrease the psychomotor activity in the alcohol-intoxicated groups of animals, when it was injected together with AII 3-7 (2 microg i.c.v.). Baclofen did not influence the retrieval process in the passive avoidance recall, and when it was given together with AII 3-7 did not change the positive action of this fragment in control groups, but significantly enhanced its action in the animals chronically treated with ethanol. Baclofen showed significant improvement of acquisition in the active avoidance test only in the alcohol-intoxicated groups. Baclofen, injected together with AII 3-7, yielded important attenuation action of AII 3-7 in the control groups in the first 3 days of test, but did not produce any changes during the fourth and fifth day of the experiment. Baclofen did not provoke any changes in activity of AII 3-7 (when it was injected together) in the acquisition of the active avoidance test in the alcohol-intoxicated groups of animals.

Analysis of Variance↗

PubMed1999

Disruption of temporo-entorhinal connections abolishes recognition memory-enhancing effect of angiotensins in rats.

In our laboratory, the positive influence of angiotensin II and its 3-7 fragment on learning and memory processes was found to be mediated by excitatory amino acids, because it was abolished by N-methyl-D-aspartate (NMDA) receptor antagonists. The purpose of the present study was to investigate whether bilateral disruption of glutamatergic temporo-entorhinal connections may have an influence on the facilitatory effect of both angiotensin peptides on recognition memory. The bilateral transections of temporo-entorhinal connections were made in 32 male rats 10 days before testing the effect of intracerebroventricular AII or AII(3-7) injection on the recognition of objects evaluated in an object-recognition test. Thirty additional rats served as sham-operated controls. The final analysis was based on 29 lesioned and 26 sham-operated animals. AII and its 3-7 fragment significantly improved object recognition in the sham-operated groups of rats. Bilateral disruption of temporo-entorhinal connections totally abolished the facilitatory effect of both angiotensins on object recognition. Moreover, bilateral disruption of temporo-entorhinal connections significantly attenuated crossings of squares and rearings, without affecting bar approaches and defecation evaluated in an open-field test. These results may suggest that the facilitatory recognition memory effect of AII and AII(3-7) requires a reciprocal glutamatergic connection between the lateral entorhinal cortex and the temporal cortex.

Angiotensin II↗

PubMed1998

Applications of the Mitsunobu reaction in peptide chemistry.

The Mitsunobu reaction--the nucleophilic substitution of an alcoholic hydroxyl group mediated by the redox system trialkylphosphine/dialkyl azodicarobxylate--is widely used in the chemistry of biologically active compounds. The paper deals with applications of the Mitsunobu reaction in amino acid and peptide chemistry. The process provides easy access to many unnatural amino acids and derivatives. Since the reaction occurs with complete inversion of the configuration at the carbinol chiral centre, it can be used for the synthesis of diastereoisomers of hydroxy- and tioprolines. Cyclization of beta-hydroxy amino acid containing peptides under Mitsunobu reaction conditions leads to a constrained peptide that mimics the stabilizing reverse turn secondary structure.

Amino Acids↗

PubMed1998

6-OHDA bilateral lesions to the nucleus septi lateralis attenuate vasopressin improvement of recall in rats.

The investigation was aimed at investigating whether the dopaminergic projection arriving at the nucleus septi lateralis (NSL) is involved in the facilitatory effect of vasopressin (AVP) on memory retrieval. The bilateral 6-OHDA lesions to the NSL were made in 20 male Wistar rats before testing the intracerebroventricular (i.c.v.) AVP injection on recall in a passive avoidance situation. Eighteen additional rats served as sham-operated controls. Thirty minutes before surgery rats were pre-treated with an intraperitoneal injection of 25 mg kg-1 of desmethylimipramine, an inhibitor of norepinephrine uptake. Sixteen lesioned and 16 sham-operated rats were included in the study. AVP (1 microgram, i.c.v.) given 15 min before the retention testing significantly improved latencies both in lesioned and in sham-operated rats in comparison with the respective i.c.v. saline-injected animals. However, bilateral lesions to the NSL significantly diminished the facilitatory effect of AVP on recall. The insignificant decrease of spontaneous psychomotor activity in rats lesioned to the NSL was unlikely to interfere with the cognitive effect of AVP. These results suggest that dopaminergic projection to the NSL is involved in the facilitatory effect of AVP on the retrieval process in a passive avoidance situation.

Animals↗

PubMed1998

The effect of baclofen and AP-7 on selected behavior in rats.

Synaptic plasticity, cognitive performance, learning, and memory appear to be determined by the balance between GABAergic inhibitory and glutaminergic excitatory amino acids (EAA). To evaluate this role of amino acids the effects of baclofen (0.5 mg/kg IP), GABA-B receptor agonist and AP-7 (5 nmol ICV)-NMDA (N-methyl-D-aspartate) receptor antagonist on the processes of retrieval, consolidation of conditioned reflexes, object recognition, and locomotor activity were tested in rats. Neither AP-7 nor baclofen alone changed locomotor activity, but coadministration of AP-7 and baclofen significantly decreased this activity in the open-field test. Neither AP-7 nor baclofen influenced retrieval or consolidation in the passive avoidance situation when administered alone. Significantly prolonged retrieval and consolidation were observed when AP-7 and baclofen were given together. We did not find differences in effects of either AP-7 or baclofen on object recognition, regardless whether administered alone or in combination.

2-Amino-5-phosphonovalerate↗

PubMed1998

6-OHDA lesions to amygdala and hippocampus attenuate memory-enhancing effect of the 3-7 fragment of angiotensin II.

We have previously shown that facilitatory effect of angiotensin II (AII) on the retrieval of memory is mediated by the dopaminergic system. In the present study, we searched for the influence of the 3-7 fragment of angiotensin II [AII(3-7)] on the retrieval processes in a passive avoidance situation after bilateral 6-OHDA lesions to the central amygdala (CA) and the CA4 field of the hippocampus (HI). AII(3-7) given 15 min before the retention testing, at the intracerebroventricular dose of 1 nmol, significantly prolonged avoidance latencies in sham-operated rats (i.e. improved retrieval of memory for the electric footshock experienced during the learning trial). Bilateral lesions to CA totally abolished, and to HI significantly diminished, this facilitatory effect. An increase of spontaneous locomotor activity in rats lesioned to CA and a decrease in rats lesioned to HI were unlikely to interfere with the cognitive effect of AII (3-7). These results suggest that the anatomical substrate of facilitating retrieval of information activity of AII(3-7) is closely related to the dopaminergic projection from the ventral tegmental area and substantia nigra to CA and HI.

Adrenergic Agents↗

PubMed1998

The participation of nitric oxide in the facilitator effect of arginine vasopressin on memory.

In this study we tested the hypothesis that nitric oxide (NO), which function as a novel type of inter-cellular messenger in the central nervous system (CNS) participated in the facilitator effect of arginine vasopressin (AVP) on learning and memory. Recent investigations have provided evidences that inhibition of NO synthesis attenuated the vasodilatation caused by AVP, and inhibited the improvement of learning and memory evoked by angiotensin II. AVP as well as pharmacologically produced increase in endogenous NO facilitates the consolidation of shock avoidance learning. We evaluated the behavioural effects of AVP at dose 1 microgram after the inhibition of NOS by NG-nitro-L-arginine methyl ester (L-NAME) at dose 10 micrograms, and after the injection of endogenous donor of NO -L-arginine- 10 micrograms in the retrieval of passive avoidance situation, and in consolidation of active avoidance responses. The locomotor activity of all investigated drugs was tested in the open field test. AVP facilitated the recall of passive avoidance responses and consolidation of active avoidance responses. Neither the increase of NO concentration after the injection of L-arginine nor the decrease of NO after the inhibition of NOS by L-NAME changed the behavioural effects of AVP. L-arginine increased the psychomotor behaviour and L-NAME decreased the activity of animals in the "open field" test. L-arginine itself improved the consolidation of active avoidance responses. Our results indicate that central action of AVP is probably independent of NO concentration in the brain.

Animals↗