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Biomedical subjects

K Nieber

Publications and source records attributed to K Nieber.

65 records · Page 4Linked to original sources
PubMed1983

Effect of desamino-cholecystokinin-octapeptide (CCK-7) on the intraluminal pressure and myoelectrical activity of the gall-bladder, stomach, and small intestine in conscious dogs.

Desamino-cholecystokinin-octapeptide (CCK-7) increased the gall-bladder pressure and decreased the gastric pressure following i.v. infusion in conscious dogs. In small intestine and Heidenhain pouch CCK-7 exerted an initial excitatory effect followed by an inhibitory effect on intraluminal pressure and peristalsis. In all organs the effect of CCK-7 on pressure was correlated with a change of spike discharge. CCK-7 is more potent on gastrointestinal motor activity than a Boots preparation of pancreozymin. The results suggest that CCK-7 at doses within the physiological range could be involved in the regulation of gastrointestinal motility.

Animals↗
PubMed1982

[Substance P - a neuropeptide transmitter].

a survey is given concerning the effects of undecapeptide Substance P (SP). SP is a peptide with eleven amino acids. It is localized in the nervous system and out of it. SP seems to play an important physiological role in neuronal functions, blood pressure, secretion and smooth muscle activity. In these functions SP has a dual action. From this dual action it is concluded that SP acts as modulatory or regulatory peptide. The regulatory function of SP seems to be connected with the system of endogenous opiates and with the system of catecholamines. The changes of application of SP in practice are unknown up to now.

Animals↗
PubMed1982

[Differences in activity between substance P and substance P-heptapeptide as studied on the phenomenon of "gut dependence" in rats (author's transl)].

Naloxone causes a tonic contraction (= "gut dependence") of the ileum in morphine-dependent rats. This "gut dependence" can be antagonized by morphine (2.5 X 10(-7) g/ml). Substance P-undecapeptide (SP1-11) produces a tonic contraction of the ileum in morphine-independent rats and also in morphine-dependent rats. In the latter, this tonic contraction is comparable with the naloxone-induced contraction. When morphine-dependent rats with naloxone-induced "gut dependence" are given SP1-11, they show an additional increase in tonus followed by a rapid tonus inhibition. Substance P-heptapeptide (SP5-11) also causes a naloxone-like contraction in both the morphine-dependent and the morphine-independent rats. In contrast to SP1-11, SP5-11 produces neither a tonus superposition nor a tonus inhibition in morphine-dependent rats with naloxone-induced "gut dependence". The fact that SP5-11 does not, in contrast to SP1-11, exert these two effects (tonus superposition and subsequent tonus inhibition) is indicative of differences between the mechanisms of the two Substance P sequences.

Animals↗
PubMed1982

Different action of substance P on gastric and ileal smooth muscle.

On the smooth muscle of the gastrointestinal system, substance P (SP) has both a stimulatory and an inhibitory effect. The effect depends on dose and route of application (in vivo or in vitro). In vivo (stomach and ileum of dog) at low dose, SP inhibits the amplitude and frequency of peristaltic contractions without influencing tone. In higher dose, SP stimulates the tone and inhibits peristaltic contractions. In vitro (circular preparations of fundus and corpus of guinea pig stomach and longitudinal preparations of guinea pig ileum), only the stimulatory effect of SP is found. At high SP concentrations, stimulation of tone is accompanied by a postexcitatory inhibition of peristaltic contractions. The results demonstrate that there are two types of inhibitory activity of SP on contractions of smooth muscles. One of these can be seen only during in vivo experiments at low concentrations. This primary inhibitory effect could be the result of the action of SP on the neuronal elements. The other kind of inhibitory effect on contraction is a secondary effect, and is only induced at high concentrations of SP and only in connection with a stimulatory effect on tone. The secondary inhibitory effect of SP may be connected with the direct effect of SP on smooth muscle cells.

Animals↗
PubMed1981

Contractile response of longitudinal and circular smooth muscles of guinea pig stomach and ileum to substance P.

The mechanical activity of longitudinal and circular smooth muscle preparations from fundus, corpus, and antrum of guinea pig stomach and distal ileum of guinea pig were recorded and the effect of substance P (SP) was measured. In physiological concentrations (10(-13) - 10(-7) mol/l) SP activates the tone of circular muscle strips from fundus and corpus of guinea pig stomach. Quite opposite is the situation with respect to the SP tonic activation in the muscle layers of guinea pig ileum. Here SP activates only the tone of longitudinal muscle layers. In these concentrations SP induces no or only very small contractile response in longitudinal muscle strips of fundus and corpus and in circular muscle preparations of distal ileum. The greater sensitivity to SP appears to result for the longitudinal muscle layer of ileum followed by the circular layer of fundus and corpus.

Animals↗
PubMed1978

A selective tonic activation of gastrointestinal smooth muscle by substance P.

Mechanical and electrical activity of smooth muscle preparations from fundus, corpus, and antrum of guinea-pig stomach and from distal ileum of guinea-pig were recorded, and the effects of Substance P were examined. Substance P activated selectively the tonic activity of corpus, fundus, and ileum of guinea-pig before and after blockade of phasic contractions. The tonic activation of Substance P is accompanied by increasing of number and amplitude of spike discharges and by decreasing of amplitude of slow potentials in corpus. The tonic activation of Substance P is potentiated parallel with reduction of Ca++ up to 0.6 mmol.

Animals↗