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Biomedical subjects

M Poppei

Publications and source records attributed to M Poppei.

At least 19 recordsLinked to original sources
PubMed1983

[Effect of substance P on blood pressure in rats, with and without hypokinetic stress].

The effect of substance P (SP) on blood pressure was studied in normotensive rats and in rats with hypokinesia-induced hypertension. To characterize the SP effect, the influence on the blood pressure value, intra-individual variation and interindividual changes was investigated. Whereas SP corrected the hypokinesia-induced changes (increased blood pressure, increase in the intra-individual blood pressure variations) in the stressed animals, no SP effect was observed in the normotensive control rats. These findings are discussed with a view to the assumed ability of SP to act as a regulatory peptide (regulide).

Animals↗
PubMed1983

[Significance of the time of administering substance P on learning and memory in rats].

We studied the influence of time and period of application of substance P (SP) on type and size of the effects on learning in Wistar rats. Treatment with SP before acquisition training had a fascillitating effect on learning. If SP was applied from the 1st or 3rd d of acquisition training there was no effect; if given from the 2nd d an inhibition was found; if given from the 4th d the consolidation of memory became finished. We found during the inhibition of exploration if SP was given acquisition training only (and no longer during the retention test). Some possible explanations of these differing effects of SP are discussed.

Animals↗
PubMed1982

Action of substance P and an SP-hexapeptide analogue on avoidance learning in rats.

The effects of Substance P (SP) (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-MetNH2) and of a SP hexapeptide analogue (SP-A) (Lys-Phe-Ile-Gly-Leu-MetNH2) on active avoidance learning were investigated in spontaneously hypertensive rats (SHR) and Wistar rats. Active avoidance learning was slower in SHR than in Wistar rats. SP-A "normalized" the slower active avoidance learning in SHR, whereas SP did not. Some possible causes of this difference as well as the mechanism of the normalizing effect of SP-A are discussed.

Animals↗
PubMed1982

[Asymmetrical distribution of noradrenaline in the neocortex, hippocampus and adrenal glands of rats and changes with chronic activity restriction].

The norepinephrine content of neocortex, hippocampus, and adrenals of adult male Wistar rats was estimated. In normal rats an asymmetrical right-left-distribution of the norepinephrine content was found. Neocortex and hippocampus showed a contralateral, neocortex and adrenals an ipsilateral ratio. Chronic stress cancelled this right-left asymmetry of norepinephrine distribution. In brain the levelling appeared earlier than in adrenals.

Adrenal Glands↗
PubMed1981

Action of substance P and an analogue on blood pressure and avoidance learning in rats with spontaneous hypertension (SHR).

Substance P (SP) and an analogue (Lys-Phe-Ile-Gly-Leu-MetNH2 = EH) were tested in acute experiments on the blood pressure in the intact rat anaesthetized with urethane. A biphasic response, consisting of an initial depressor, followed by a pressor component, was seen. In low concentrations, SP decreases blood pressure, in medium concentrations SP produces a pronounced biphasic response, in high concentrations SP produces only hypertensive reactions. In chronic experiments, SP-peptides act also in different directions. After EH, disorders in avoidance learning were completely eliminated from 10 weeks old spontaneously hypertensive rats (SHR) or conditionally from SHR age 14 or 26 weeks. Elevated blood pressure in SHR aged 26 weeks was reduced by EH. Blood pressure in SHR aged 14 weeks was almost unaffected by EH and blood pressure went up in ten weeks old SHR. SP had a weaker action in comparison with EH. These results are in agreement with the hypothesis proposed by Oehme and co-workers [11-13] that SP can act as a regulatory peptide (="regulide").

Animals↗
PubMed1981

Pyridostigmine administration in newborn rats prevents permanent mental ill-effects produced by maternal deprivation.

Maternal deprivation from Day 3 to Day 14 of life, i.e., separation of the pups from their mother animals during this developmental period for 16 hours each day, gave rise to highly significantly decreased learning capability and memory capacity in adulthood associated with significantly decreased acetylcholinesterase activity in the brain. These permanent ill-effects of the brain, produced by maternal deprivation of newborn rats, could be prevented by the acetylcholinesterase inhibitor pyridostigmine when administered from Day 1 to Day 14 of life. In view of these findings, teratogenic mental ill-effects, produced by psychosocial and/or nutritional deprivation during brain development, appear to be preventable by correcting abnormal neurotransmitter concentrations during this critical period of brain organization.

Acetylcholinesterase↗
PubMed1980

Substance P--new aspect to its modulatory function.

The paper deals with a modulatory function of Substance P (SP) (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-MetNH2) with bearing on nociperception, behaviour, and norepinephrine uptake. The effect of SP on both nociperception and behaviour was found to depend on the original condition of the individuals. The individual response time of mice to thermic stimuli becomes standardized by Substance P in the hot-plate test. Disorders in acquisition of avoidance reactions caused by noiseborne stress were found to be fully normalized by SP, like certain vegetative parameters, such as blood pressure, heart rate, and respiratory rate. SP was found to inhibit or stimulate norepinephrine uptake of hypothalamus preparations depending on the experimental conditions. It is recommended to name peptides of the above type of action as "regulatory peptides" (regulides).

Acoustic Stimulation↗
PubMed1980

[Edematous changes in the ultrastructure of the neocortex of Wistar rats following the application of angiotensin II].

In 80 Wistar rats were investigated the prolonged action of Angiotensin II in a dosage of 0,05 mg/kg/die ip. appl. on microstructures of the sensomotoric cortex. It is observed, after the first application, a biphasic reaction of brain vessels, in the beginning a pronounced vasodilatation (5 min p.-inject) which 10 min later turn into a vasoconstriction. In correlation with the applications frequency the repeated injection of the octapeptide leads to perivascular edemas. Neurons of the sensomotoric cortex show strong swellings, which later turn in to involutions. Pronounced destructions of mitochondria are demonstrable. Conceivable mechanisms were discussed.

Angiotensin II↗
PubMed1980

Effects of a substance P-analogue on blood pressure and avoidance learning of rats with spontaneous hypertension.

A shortened and modified eledoisin-hexapeptide sequence (Lys-Phe-Ile-Gly-Leu-MetNH2) was tested for their action on avoidance learning and blood pressure of rats with spontaneous hypertension (SH-rats) and intact Wistar rats. Both groups were 10, 14, and 26 weeks of age. Disorders of avoidance learning and elevation of blood pressure were likely to aggravate along with growing age of SH-rat. The used eledoisin-hexapeptide sequence is related to the essential C-terminal pentapeptide sequence of Substance P (SP). After injection of the used hexapeptide at doses of 250 microgram/kg intraperitoneally disorders in avoidance learning were completely eliminated from ten-week SH-rats or conditionally for SH-rats aged 14 and 26 weeks. Elevated blood pressure in SH-rats aged 26 weeks was reduced by the hexapeptide from 220 Torr to approximately 190 Torr. Blood pressure in SH-rats aged 14 weeks, originally about 180 Torr, was almost unaffected by the hexapeptide. Blood pressure went up from about 150 Torr to 190 in ten-week-old Sh-rats. A hypothesis was made about the mode of action of Substance P and related peptides.

Animals↗
PubMed1980

[Effect of a substance P analog on sleep deprivation].

The injection of 250 microgram/kg SP-analogue (Lys-Phe-Ile-Gly-Leu-MetNH2) is able to restore the reduced or disturbed delta activities and paradoxical sleep periods of the sleeping EEG in chronically stressed rats. Thus it has been proved that Substance P, which we would like to term as an ,,regulatory peptide" (equal to regulide) has a modulating function.

Animals↗
PubMed1979

Conditioned-reflex learning of normal juvenile and adult rats exposed to action of substance P and of an SP analogue.

The actions of both Substance P, a potential neurotransmitter or modulator and of a shortened analogue on learning and memorizing processes are reported in this paper. Sixty male rats, aged 22, 14, and 10 weeks, were exposed to Substance P (Arg-Pro-Gln-Gln-Phe-Gly-Leu-MetNH2) and to a shortened hexapeptide analogue (Lys-Phe-Ile-Gly-Leu-MetNH2), doses being 250 microgram/kg and 500 microgram/kg, to test their action upon learning and memorizing processes, such as acquisition, retention, and ecphoration, by means of a conditioned-reflex locomotor defense method. Response time of all three age groups as well their retention and ecphoration were normal under the impact of hexapeptide. The effects of Substance P were decline of retention in juvenile animals (10 weeks of age) and coupling between the processes of central-nervous afference synthesis, on the one hand, and the efference integral related to motoricity, on the other, in both juvenile and adult animals. A retention test was conducted and showed that discontinuation of application of either peptide over 4 d was followed by complete inhibition of ecphoration. Learning and memorising processes were restorable by reapplication of the peptides. These findings were defined as "state-dependent learning". Only slight variation under the impact of both Substance P and the analogue was recordable by non-invasive measurement of systolic blood pressure.

Aging↗
PubMed1979

Action of substance P on neurotico-hypertensive rats.

The action of an eledoisin-hexapeptide analogue (EH) upon learning and memorising processes of 48 male Wistar laboratory rats aged between 5 and 6 months was studied and is reported in this paper. The animals suffered from neurogenic hypertension which had been experimentally induced by applying emotional stress. A comparison between the action of EH (Lys-Phe-Ile-Gly-Leu-MetNH2) and that of Substance P (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-MetNH2) on conditioned-reflex learning in the intact rat had been reported by the authors in one of their previous papers [7]. The following results were obtained with regard to EH and its action upon rats with neurogenic hypertension. The learning process was favoured, as it had been by 2 or 3 weeks of exercise. Defective learning and memorizing process as well as impaired behavioural patterns, interpreted as neurotic phenomena, were normalized by doses of 250 microgram/kg and 500 microgram/kg. Blood pressures were reduced, depending on dosage. The action of the EH analogue used on the central nervous system was stronger than that on blood pressure. Discontinuance of peptide application was followed by the phenomenon of "state-dependent learning". The results are likely to suggest possible involvement of such peptide sequences in the regulation of processes which are relevant to the whole. That effect is of particular interest, as Substance P is under discussion as a transmitter or modulator in mammals.

Animals↗
PubMed1978

[Learning and memory processes during postnatal ontogenesis in rats with spontaneous hypertension].

The examination of learning and memory processes by a conditional reflectory locomotor avoidance reaction on 8-, 10-, 12-, 14-, 16-, 20-, 26-, and 50-week-old rats with spontaneous hypertension (SHR Okamoto/Aoki) revealed, up to an age of 20 weeks, correlations between the height of blood pressure and learning and memory performance by analogy with parameters of the hydrocarbon metabolism [1,2]. Three stages were observed: Stage I: Juvenile animals (8--10 weeks) with mean systolic blood pressure values of 150 to 170 torr showed a comparatively low restriction of learning and memory processes. Stage II: In adult animals (12--20 weeks) with mean systolic blood pressure values of 180 to 210 torr learning was inhibited by about 50%, while retention of memory was completely disturbed. Stage III: In old animals (26--50 weeks) with mean systolic blood pressure values above 200 torr the faculty to learn a conditional avoidance reflex was virtually lost. Destruction or blockage of hypothalamic behavioral substances are assumed to cause the derangement of learning and memory processes in spontaneously hypertensive rats.

Aging↗