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Biomedical subjects

R Rathsack

Publications and source records attributed to R Rathsack.

At least 37 records · Page 2Linked to original sources
PubMed1987

[Changes in substance P concentration in rat plasma under different conditions of blood letting].

The influence of various conditions at blood-letting on the concentration of SP in the plasma was investigated in male Wistar rats as background for following studies on effects of noxae. Narcotic substance (hexobarbital, ether), CO2-suffocation and the mechanical kinds of killing (cervical dislocation, occipital hit, decapitation) influence the SP concentration in different ways. It is assumed SP concentration in plasma after cervical dislocation to be the best corresponding value for physiological conditions.

Anesthesia↗
PubMed1987

Relationship of substance P to catecholamines, stress, and hypertension.

This paper presents results on the function of the adrenal medulla, especially the influence of substance P (SP) on the cholinergic-adrenergic interaction. Interconnections between the function of SP and its role in the development and maintenance of hypertension as well as its role in stress and adaptation are investigated. Substance P acts only in situations with an increased nervous activity, for example, after stress-induced activation of the pituitary-adrenal and sympathetic-adrenal axis. Substance P normalizes stress-induced disorders by maintaining homeostasis in the catecholamine system. The basis of the antistress effect is the modulation of both biosynthesis and release of catecholamines in the adrenals. The homeostasis effect of SP, as well as the antistress effect do not require the complete sequence of the molecule. The N-terminal SP fragment is fully active and has no side effects.

Adrenal Glands↗
PubMed1987

Substance P in human essential hypertension.

Substance P (SP) plays an important role in central nervous and peripheral blood pressure regulation. Its effects include modulating influence on the adrenergic system and inhibition of stress-induced plasma noradrenaline increase in animal studies. In patients with essential hypertension (n = 45, WHO stages 1 and 2) the SP-like immunoreactivity (SPLIR) was found significantly (p less than 0.01) lower (1.36 +/- 0.23 pg/100 microliters) than in 24 normotensive subjects (4.54 +/- 0.72 pg/100 microliters). Furthermore, the influence of a mental stress test on SPLIR was investigated in patients with essential hypertension (n = 11, WHO stage 1) and compared with nine normotensive subjects. Whereas in normotensive subjects plasma SP increased under a standardized mental arithmetic test (4.03 +/- 0.48 to 4.74 +/- 0.56 pg/100 microliters), in hypertensive patients a decrease of SP from lower baseline levels (2.85 +/- 0.54 to 2.57 +/- 0.54 pg/100 microliters) was demonstrated. The significantly different changes of plasma SP in normotensive and hypertensive subjects under mental stress conditions had the opposite direction in comparison with the adrenergic reaction [higher and prolonged increase of plasma noradrenaline (NA) in the hypertensive group]. Under antihypertensive drug treatment with prazosin (4.5 mg/day, n = 10) or with captopril (450 mg/day, n = 10) an increase of plasma SP was registered. The results support the participation of SP in the pathogenesis of human hypertension and in therapeutic mechanisms. Lower plasma levels and decreased responsiveness of SP possibly represent the enhanced stress sensitivity in primary hypertension.

Adult↗
PubMed1984

[Cellular distribution of substance P in the rat adrenal medulla].

Substance P-like immunoreactivity (SPLIR) has been found in fibres and the surroundings of ganglion cells and in a new cell type of rat adrenal medulla, using the indirect immunohistochemical method. These SPLIR-cells are characterized by their localization in the connective tissue in close vicinity of vessels and by acidophilic staining in HE-procedure. Relationships are discussed between the localization of substance P in the adrenal medulla and possible interactions with catecholamines with respect to stress.

Adrenal Medulla↗
PubMed1983

[Behavior of blood pressure and substance P-like immunoreactivity (SPLIR) in plasma of rats with genetically fixed hypertension (SHR) under chronic intermittent immobilization].

The influence of chronic immobilization on blood pressure and on substance P-like immunoreactivity (SPLIR) in blood plasma was examined in 11-week-old male spontaneously hypertensive rats (SHR) and male normotensive Wistar Kyoto rats (WKY). In SHR chronic immobilization caused a stop of the genetically fixed development of hypertension at the level already reached. Also, SPLIR in blood plasma was lower compared with a SHR control group without immobilization. In WKY rats chronic immobilization has no influence on blood pressure and SPLIR. The observed variations in SPLIR and blood pressure under the influence of chronic immobilization is discussed in relation to a possible function of substance P in the development of hypertension.

Animals↗
PubMed1983

Evidence of decreased plasma substance P levels in human essential hypertension and influence of prazosin treatment.

Patients with essential hypertension (n = 45) had significantly lower substance P plasma levels (13.6 +/- 2.30 pg/ml) in comparison with a group of 24 normotensive subjects (45.4 +/- 7.18 pg/ml) analyzed by radioimmunoassay. Prazosin treatment for 2 weeks with 4.5 mg/day enhanced the substance P plasma level depending on its antihypertensive effect. Norepinephrine concentration in plasma was also elevated by prazosin. Dipeptidylpeptidase IV, dopamine-beta-hydroxylase and plasma renin activity were not changed significantly. The results indicate the participation of substance P in pathophysiological processes of human essential hypertension.

Adult↗
PubMed1983

Substance P-like immunoreactivity in plasma and adrenal medulla of rats with spontaneous hypertension and WKY rats under acute stress.

The substance P-like immunoreactivity (SPLIR) of plasma and adrenal medulla from spontaneously hypertensive (SHR) and normotensive WKY rats was measured by a sensitive and highly specific radioimmunoassay for substance P (SP). With increasing age the level of substance P in the adrenal medulla decreased, whereas the SP content of the plasma remained constant in both groups. The SPLIR in plasma of SHR was significantly lower than in normotensive WKY rats. After acute stress the SPLIR, especially of the adrenal medulla of WKY rats, increases, and decreases in SHR. The reason for this different behaviour is discussed and it is assumed that hyperreactions in the sympathetic system may be responsible.

Adrenal Medulla↗
PubMed1982

Relation of substance P to stress and catecholamine metabolism.

Most research on substance P deals with its presumed function in the nervous system. Both excitatory and inhibitory actions have been observed in pharmacological studies. For example, substance P has a dual action on nociception in mice: it produces analgesia or hyperalgesia, depending on the dose and on the individual sensitivity to pain. This is interpreted to mean that substance P is capable of normalizing responsiveness to pain. Thus substance P could be classified as a regulatory peptide, or 'regulide'. A similar normalizing action of substance P was found in stress-induced disorders of sleep, behaviour and blood pressure in rats. The mechanism of this normalizing action is not yet clear. The decrease in activity observed for dopamine beta-hydroxylase and phenylethanolamine N-methyltransferase in adrenal glands of rats treated with the peptide may serve as a preliminary hypothesis.

Adrenal Glands↗
PubMed1975

[On the composition of fatty acids in Chlorella pyrenoidosa under the influence of dimethyl- and diethylaminoazobenzene (author's transl)].

The composition of bulk fatty acids in Chlorella pyrenoidosa under the influence of the carcinogenic dimethylaminoazobenzene and the non carcinogenic diethylaminoazobenzene was examined. In the presence of dimethylaminoazobenzene cultivated algae showed parallel to morphological changes distinct deviations in the composition of their fatty acids compared with the control. This especially concerns the unsaturated C18-fatty acids as the C16:0-, C16:2- and C16:3-acids respectively. By treatment of algae with diethylaminoazobenzene no morphological variations were observed and only little changes in composition of their fatty acids was demonstrated.

Azo Compounds↗