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Biomedical subjects

K Wiśniewski

Publications and source records attributed to K Wiśniewski.

At least 55 records · Page 3Linked to original sources
PubMed1995

The effect of vasopressin analogue [d(CH2)5(1),Tyr(Me)2]AVP on memory process in rats with experimental amnesia.

We investigated the effect of a single 2 micrograms dose of vasopressin (AVP) analogue [(CH2)5(1),Tyr(Me)2]AVP on the processes of retrieval of conditioned reflexes in rats with experimentally induced amnesia. The models used were: electroconvulsive shock (ECS) and hypoxia. It severely impaired the memory processes. The AVP analogue [d(CH2)5(1),Tyr(Me)2]AVP facilitated retrieval of passive avoidance in all animals.

Animals↗
PubMed1995

Influence of sodium nitroprusside "NO-donor" on psychotropic activity of angiotensin II.

In this work we compared the influence of sodium nitroprusside [SNP] (a NO donor) on behavioural effects of angiotensin II [AII] in rats. The motility, stereotypy, learning of conditioned avoidance responses and recall of passive avoidance behaviour allowing to avoid aversive stimulation were estimated. The intracerebroventricularly injection--15 min before the experiment--of AII, SNP and AII combined with SNP did not produce changes in psychomotor activity in open field, not significantly accelerated acquisition of conditioned avoidance responses and significantly improved recall of the passive avoidance. AII, SNP and AII with SNP applied immediately before the experiment intensified stereotypy evoked by apomorphine in the dose of 1 mg/kg and amphetamine in the dose of 7.5 mg/kg given intraperitoneally. These results show that; 1) sodium nitroprusside as a donor NO participates in memory and learning processes, 2) overproduction of NO did not change behavioural effects of AII in these experiments.

Angiotensin II↗
PubMed1994

Central activity of peptide Gly-Pro-Hyp--the main component of collagen degradation products mixture.

The effect of tripeptide Gly-Pro-Hyp on the central nervous system was studied. The peptide Gly-Pro-Hyp is a main component of the mixture of collagen type I degradation products obtained by 6-h digestion with bacterial collagenase. The investigated peptide in the doses 1 microgram, 2 micrograms, and 5 micrograms significantly reduces the psychomotor activity of animals, intensifies haloperidol-induced catalepsy and enhances stereotypy behaviour after apomorphine administration. The central activity of Gly-Pro-Hyp is similar to the action of collagen degradation products mixture. This suggests that this peptide may be the active substance responsible for the effects of degradation products of collagen type I.

Amino Acid Sequence↗
PubMed1994

Effects of vasopressin and analogue [d(CH2)1(5), Tyr (Me)2, Val4, delta 3Pro7)] AVP on learning and memory in rats chronically treated with ethanol.

Rats with impaired active and passive avoidance induced by chronic administration of ethanol were studied. Vasopressin (AVP) and analogue (d(CH2)1(5), Tyr (Me)2, Val4, delta 3Pro7] AVP (icv, 2 micrograms) eliminated the toxic effect of ethanol, and analogue AVP improved retrieval of passive avoidance situation in both control and postalcohol groups of rats. Chronically administered ethanol markedly depressed the ability to learn. AVP administered icv markedly delayed extinction of conditioned avoidance situation in both groups of rats, and did not influence acquisition in this test. Analogue AVP has no influence on extinction and acquisition in the control and post-alcohol groups of rats.

Animals↗
PubMed1992

Pharmacological and physicochemical properties of collagen breakdown-products.

It has been found that the pharmacologically active, low molecular products obtained by digestion of telopeptides-deprived type I collagen with bacterial collagenase is a heterogenous mixture of at least 21 peptides of different molecular weight. They contain 3 to 15 amino acid residues. About 80% of them are tripeptides of the sequence Gly-Pro-X. The most abundant are two peptides: Gly-Pro-Hyp and Gly-Pro-Ala. The peptides injected into the lateral cerebral ventricle of the rat evoked some behavioral effects. They decreased the psychomotoric activity (evaluated with Lat's test) and increased the cataleptic action of haloperidol. On the other hand, they did not exert any effect on amphetamine-induced stereotypy and did not counteract the apomorphine-induced stereotypy.

Amino Acid Sequence↗
PubMed1992

The effect of collagen degradation products (CDP) on the central nervous system (CNS).

Rat collagen type I was digested with bacterial collagenase. The peptides obtained were submitted to gel filtration on Sephadex G-25. Two fractions differing in molecular weight (CDP I-3000 D and CDP II-1200 D) were obtained. These fractions administered to rats were found to have an inhibiting effect on the central nervous system (CNS) in Lat's test and the mobility of the animals recorded on a motimeter was found to be reduced. This effect was dependent on the peptide dose and occurred after intravenous (iv) as well as intraventricular (icv) injection.

Animals↗
PubMed1992

Angiotensin II--derived peptides devoid of phenylalanine in position 8 have full psychotropic activity of the parent hormone.

In this work we compared in rats the influence of heptapeptide 1-7-angiotensin II, hexapeptide 2-7-angiotensin II, pentapeptide 3-7-angiotensin II and angiotensin II on motility, stereotypy, learning of conditioned avoidance responses and recall of passive avoidance behaviour allowing to avoid aversive stimulation. The 4 peptides administered 15 min before the experiment, tended to increase the number of crossings, rearings and bar approaches in open field, significantly accelerated acquisition of conditioned avoidance responses and improved recall of the passive avoidance. All the peptides applied immediately before the experiment intensified stereotypy evoked by apomorphine in the dose 1 mg/kg and amphetamine in the dose 6.5 mg/kg given intraperitoneally. These results show full psychotropic activity of the examined fragments of angiotensin II, comparable with the activity of the parent octapeptide. Our previous hypothesis that the Val-Tyr-Ile-His-Pro fragment of angiotensin II is responsible for the psychotropic activity evoked by angiotensins in rats is thus confirmed.

Angiotensin I↗
PubMed1992

[Attempts at measuring low radioactivity using a Tristan-1024 spectrometer].

A method for measurement of cesium and potassium-40 in environmental samples with the use of a gamma Tristan-1024 spectrometer was presented. The method involves taking into account the influence of the Compton effect on the shape of the observed spectrum, and then counting of the impulses in appropriate energetic intervals. The results showed that it is possible to rapidly measure K-40 activities exceeding 30 Bq/kg as well as the activities of Cs-137 and Cs-134 isotopes of an order of several Bq/kg in so-called "fresh" sample, with no need for applying expensive preparative treatment. The low cost of measurements, as compared with radiochemical methods, is an advantage of the presented method.

Cesium Radioisotopes↗
PubMed1991

The 3-7 fragment of angiotensin II is probably responsible for its psychoactive properties.

The abilities of angiotensin II-(3-7)-pentapeptide (A-II-(3-7), 1 nmol) and angiotensin II (A-II, 1 nmol) to influence rat's psychomotor and cognitive behaviours were compared. Both peptides, given intracerebroventricularly (i.c.v.), 15 min before the experiment, increased number of crossings, rearings and bar approaches in the open field. A-II-(3-7) as well as A-II, at the same doses and routes, significantly intensified stereotypy produced by apomorphine (1 mg/kg) and amphetamine (6.5 mg/kg), both given intraperitoneally. The 3-7 fragment of A-II and A-II in equimolar doses (1 nmol, i.c.v.) were similarly effective in improving learning of conditioned avoidance responses and recall of a passive avoidance behaviour. Taken together, these data and our previous findings indicate that, in rats, the 3-7 fragment of A-II is responsible for the psychoactive properties of angiotensins.

Analysis of Variance↗
PubMed1990

Some behavioural effects of captopril in rats.

1. Effects of inhibition of angiotensin converting enzyme (ACE, EC 3.4.15.1) in brain on psychomotor, exploratory, stereotyped and cognitive behaviour in rats were investigated. To inhibit brain ACE captopril (D-3-mercaptopropanoyl-L-proline) was given orally (p.o., 50 mg/kg) or intracerebroventricularly (i.c.v., 5 micrograms/rat). 3. Captopril given p.o. but not i.c.v. significantly enhanced stereotypy, overall number of conditioned avoidance responses, and decreased blood pressure. 4. No statistically significant influence of captopril given by either route on the number of crossings, rearings and bar approaches in the open field, performance of passive avoidance and number of correct choices as well as the speed of running for food in the T-maze was observed. 5. In conclusion, a small decrease of the activity of nigrostriatal dopaminergic system caused by the decrease of AII and/or increase of bradykinin, substance P, enkephalins and neurotensin in brain resulting from ACE inhibition is postulated.

Administration, Oral↗
PubMed1990

Alpha 1 and alpha 2-adrenergic receptor blockade influences angiotensin II facilitation of avoidance behavior and stereotypy in rats.

Pretreatment of rats with prazosin (PRA), an alpha 1-adrenergic receptor blocker, abolished the increased rate of learning of conditioned avoidance responses stimulated by intracerebroventricular angiotensin II (AII) administration. Yohimbine (YOH), an alpha 2-receptor blocker, reversed the effect of AII. PRA did not affect, and YOH abolished, the improvement of recall of a passive avoidance behavior caused by AII. The stereotypies produced by apomorphine (APO) and amphetamine (AMP) were enhanced by AII. PRA changed neither stereotypy, but it abolished the AII effect in both cases. YOH did not alter APO stereotypy and abolished the enhancement of that behavior caused by AII. YOH increased AMP stereotypy and had an additive effect with AII. No significant changes of exploratory motor activity were caused by PRA, YOH, or their combination, with AII. These findings indicate that functioning alpha 1- and alpha 2-adrenergic receptors are necessary for the facilitation of learning by AII, while only alpha 2-receptors appear to be involved in AII improvement of recall. The central dopaminergic system may in part be responsible for the modulation by PRA and YOH of the effects of AII on learning and recall.

Angiotensin II↗
PubMed1989

Psychotropic activity of angiotensin II and its fragments Val-Tyr-Ile-NH2 and Val-Tyr-Ile-His-NH2.

Angiotensin II (A II) significantly enhanced the motor activity of rats in the open field as measured by forward locomotion, rearings and bar approaches while the tripeptide [A II(3-5)] and the tetrapeptide [A II(3-6)] were ineffective in this test. Also, the stereotyped behavior produced by apomorphine (2 mg/kg) or amphetamine (6.5 mg/kg), both given intraperitoneally, was significantly more intense in rats receiving an icv injection of A II but not A II(3-5) or A II(3-6). A II significantly increased the rate of acquisition of active avoidance while AII(3-5) and AII(3-6) were ineffective. Finally, a remarkable improvement of performance in the passive avoidance situation was caused by AII, and none by AII(3-5) and AII(3-6). These results show that 3-5 and 3-6 fragments of AII are not responsible for the psychotropic activity of their parent octapeptide and suggest that AII(3-7) pentapeptide should be the fragment in question.

Amino Acid Sequence↗
PubMed1988

The role of dopamine in the facilitatory effect of angiotensin II on impaired learning in rats chronically treated with ethanol.

Rats with impaired active avoidance induced by chronic (9 weeks) administration of ethanol were studied. Angiotensin II (ANG II) administered (ICV, 2.0 micrograms) 12 h after the withdrawal of the alcohol not only neutralized the toxic effect of ethanol but also improved learning. When administered on the 5th day after ethanol withdrawal, the effect of ANG II was weaker. Tests of stereotypy and catalepsy were used to study the possible role of the dopaminergic system in this action of ANG II. It was shown that both chronic alcohol treatment and ANG II alone increased apomorphine (1 mg/kg) and amphetamine (7.5 mg/kg) stereotypy but the effects of ANG II were greater. ANG II did not change the stereotypy induced by amphetamine but increased the stereotypy induced by apomorphine in the group of animals chronically treated with alcohol. Haloperidol-induced catalepsy was reduced in these rats. ANG II alone intensified catalepsy and eliminated the effect of ethanol. Both ANG II and alcohol increased striatal dopamine (DA) concentration. This effect of ANG II was significantly greater in the animals chronically treated with alcohol. The above changes were not observed after the DA level had been reduced by alpha-methyl-p-tyrosine (250 mg/kg), nor were changes observed in the striatal DOPAC. The results suggest involvement of the central dopaminergic system in the effect of ANG II on the ethanol-induced impairment of acquisition of active avoidance but, however, the results of the biochemical determinations of DA turnover do not provide an explanation of these changes.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1988

Angiotensin II-(3-8)-hexapeptide affects motor activity, performance of passive avoidance and a conditioned avoidance response in rats.

Angiotensin II-(3-8)-hexapeptide, at the dose of 1 nmol given intracerebroventricularly, only slightly less than angiotensin II (the same dose and route) stimulated exploratory locomotor behaviour in an open field and electromagnetic motimeter. Both peptides considerably enhanced stereotyped behaviour produced by apomorphine and amphetamine. Angiotensin II-(3-8)-hexapeptide improved recall in a passive avoidance situation as well as angiotensin II. The 3-8 C-terminus of angiotensin II enhanced acquisition of active avoidance nearly as effectively as the complete peptide. The results indicate that the effectiveness of equimolar doses of angiotensin II-(3-8)-hexapeptide and angiotensin II in improving processes related to learning and memory in rats is almost identical and thus must be independent of specific angiotensin receptors in brain to which the hexapeptide binds with about 1000 times lower affinity than angiotensin II. The stimulation of stereotypy, a dopamine-controlled behaviour, by the peptides points to the possibility of dopaminergic mediation of their psychotropic effects.

Angiotensin II↗
PubMed1987

Psychotropic effects of angiotensin II and III in rats: locomotor and exploratory vs cognitive behaviour.

One nmol of angiotensin II (AII) or angiotensin III (AIII) given intracerebroventricularly (i.c.v.) increased locomotor and exploratory activity in an open field apparatus but not in the electromagnetic field motimeter. Both peptides significantly enhanced stereotyped behaviour produced by apomorphine (2 mg/kg) and amphetamine (6.5 mg/kg) given intraperitoneally. Also, AII and AIII improved consolidation but not retrieval of memory for an appetitively reinforced spatial discrimination task in a T-maze. AII as well as AIII, given prior to the learning session on day 1, increased rate of acquisition of conditioned avoidance responses in a shuttle-box over the next 7 days. Both angiotensins, injected i.c.v. 15 min before the retention testing, remarkably (5-fold) prolonged re-entry latencies in the passive avoidance situation, suggesting facilitation of the retrieval of memory for an aversively motivated behaviour.

Amphetamines↗