Journal of Physiology and Pharmacology
Solcoseryl, a deproteinized extract of calf blood, protects the gastric mucosa against various topical irritants and enhances the healing of chronic gastric ulcerations but the mechanisms of these effects have been little studied. This study was designed to elucidate the active principle in Solcoseryl and to determine the role of prostaglandisn (PG) and polyamines in the antiulcer properties of this...
1. The evaluation of still more pretentious and complicated methods is accompanied by a decline of methodical knowledge outside of the own technical field. Interpretations or extrapolations are taken as granted without critical examination of the methodical steps applied. An example is given by re-evaluating the ⁴⁵Ca release from isolated cardiac tissue and the possible interpretations. 2. ⁴⁵Ca release...
Rapid epithelial restitution is an important protective mechanism which enables the gastrointestinal mucosa to reestablish epithelial integrity following superficial injury within hours. In this study we examined the influence of an acidic luminal pH, removal of the necrotic layer, nutrient bicarbonate, calcium and sodium desoxycholate (Na-DOC) on restitution in the rabbit duodenum in vitro and the...
The spectrum of biological rhythms exhibits characteristic principles of biological time structure which also rule the functional behaviour. With increasing period lengths the rhythms become increasingly complex. In the long-wave section the rhythmic functions find their corresponding cycles in the environment, whereas the shorter waves respresent only endogenous autonomous rhythms, which maintain...
Under the condition of rapid perfusion, the time course of contractile response of single ventricular cells to extracellular calcium (Ca) depletion and repletion identifies „fast” and „slow” cellular Ca pools. ⁴⁵Ca exchange was studied in these cells under the same conditions of on-line rapid perfusion. Four kinetically-defined compartments were distinguished: (1) A „rapid” compartment containing...
Our aims were to describe the myoelectrical activity in the single very thin layer of muscle of the canine gallbladder. The study was performed on 22 freshly removed canine gallbladders. Electrical activity was studied by the single sucrose-gap method and contractility of the tissue was measured simultaneously using a force transducer. The strips (15x1 mm) from different regions of gallbladder (fundus,...
Few site-selective serotonergic agents are currently available; in fact, most of these agents might more appropriately be termed semi-selective in that they typically bind to at least two different populations of serotonin receptors. We describe the application of structure-affinity relationship (SAFIR) studies to the development of high- affinity and/or site-selective serotonergic agents; examples...
The significance and site of adrenergic receptors involved in the control of the hypothalamic-pituitary-adrenal axis (HPA) activity was assessed indirectly by estimation of serum corticosterone levels 1 h after drug administration to conscious rats. Adrenergic drugs were given intracerebroventricularly (icv) and intraperito neally (ip), the antagonists 15 min prior to the agonists. Noradrenaline,...
Gastric mucosal integrity depends upon the balance between „aggressive” factors and „defensive” mechanisms. The formation of mucosal lesions results from the disruption of defense lines, including the breaking of unstirred mucus layer, the reduction of surface hydrophobicity, extensive exfoliation of surface epithelium, penetration of offending agents deeply into the mucosa and damage to the microvessels...
Myocytes were enzymatically isolated from large epicardial arteries of the pig. In the cell attached configuration, we studied currents through L-type Ca-channels. At 22°C, open channel conductance was 9 pS with 110 mM Ba²⁺ and 24 pS with 110 mM Ba²⁺ as charge carrier. According to the life time of the open state, 2 ’modes’ of gating are distinguished; mode 1 contributed time constants shorter than...
We investigated the effect of 2-methyl-1,4-naphtoquinone (Menadione) on sarcoplasmic reticulum (SR) Ca2²⁺ content and electrically stimulated contractions (ESCs) of single isolated myocytes of guinea-pig ventricular myocardium. The contractures initiated by means of microinjections of caffeine into the close vicinity of the cell were used as an indirect index of the SR Ca²⁺ content. Superfusion of...
According to current teaching biogenic amines are released by exocytos- is, i. e. by evacuation of amine storing vesicles or granules into the extracellular space. The release of transmitter amines is quantal, i. e. occurs in packs of transmitter molecules. These packs are assumed to be identical with vesicle contents, in other words, the smallest releasable quantum equals the amine content of one...
Even though there is no general agreement as to the mechanism of gastric mucosal protection, the consensus is that the initial brunt of luminal insults falls on the mucus layer which constitutes the only identifiable physical barrier between the gastric lumen and the mucosal surface. The continuous renewal and resilient nature of this layer efficiently counters peptic erosion of the gel, assures its...
The effects of gastrin, cholecystojdnin (CCK) and bombesin on the DNA synthesis, as a biochemical indicator of trophic action in the gastroduodenal mucosa and the pancreas have been examined in rats fasted for 48 h and in rats refed for 16 h with or without administration of specific receptor antagonists for bombesin, gastrin and CCK. Bombesin and gastrin administered three times daily for 48 h in...
To investigate whether the sampling theorem was fulfilled up to now in experimental and clinical EEG-mapping of neonates and to determine the „smearing effect” of EEG transmission by the leading media up to the skin, EEG-maps from 5 slightly anaesthetized term newborn piglets and 8 healthy human newborns were calculated. A spatial sampling rate of 1-2 cycles per cm is necessary for a sufficient reproduction...
Exposure of the rat gastric mucosa to ethanol stimulates the generation of leukotriene (LTC₄) and 15-hydroxyeicosatetraenoic acid, hut not of thromboxanes and prostaglandins. Lipoxygenase activation is not found with other topical irritants or nonsteroidal anti-inflammatory drugs. A number of gastroprotective drugs dose-dependently inhibit the stimulatory action of ethanol on mucosal LTC₄ formation...
Polyamines have been shown to stimulate cellular growth and differentiation, though their role in the prevention of acute gastric lesion induced by various noxious agents has been little studied. Epidermal growth factor (EGF) exhibits gastroprotective and ulcer healing properties due to its potent mitogenic and growth promoting action. This study was designed to compare the gastroprotective effects...
We have demonstrated recently the formation of a biologically active metabolite of prostaglandin (PG) E₁, 13,14-dihydro-PGE₁, during intravenous infusions of PGE₁ in patients with peripheral arterial occlusive disease. We have now investigated the levels of the immediate precursor of 13,14-dihydro-PGE₁ , the biologically inactive 15-keto-13,14-dihydro-PGE₁, during intravenous administration of 20...
The effects of gastrin, cholecystokinin (CCK) and bombesin on the DNA synthesis, as a biochemical indicator of trophic action in the gastroduodenal mucosa and the pancreas, have been examined in rats fasted for 48 h and in rats refed for 16 h with or without administration of specific receptor antagonists for bombesin, gastrin and CCK. Bombesin and gastrin administered three times daily for 48 h in...
The effects of extracellular K⁺ in relation to extracellular Ca²⁺ on acid production were studied. Studies were performed in vitro using isolated cells from rat stomachs, and acid production was indirectly determined by ¹⁴C-aminopyrine (AP) accumulation. In the absence of K⁺ in the incubation medium histamine-stimulated AP accumulation ratios were significantly decreased independently in the presence...