Search results for "adenosine"
showing 10 items of 542 documents
Intestinal filtration as a consequence of increased mucosal hydraulic permeability
1980
Two mechanisms have been proposed to explain the secretory action of laxative compounds in the intestine: 1. increase of the intracellular amount of cyclic adenosine monophosphate due to stimulation of the adenylate cyclase system and 2. inhibition of intestinal transfer processes, in particular the Na,K-ATPase activated sodium absorption. In a set of in vivo and in vitro experiments in rat colon it could be demonstrated that dihydroxy bile acids (deoxycholate) and diphenolic laxatives (oxyphenisatin) enhance the hydraulic permeability of the mucosal tissue. The permeability changes take place--and there is good experimental evidence--at the zonulae occludentes which bind the epithelial cel…
Adenosine activates a potassium conductance in guinea-pig atrial heart muscle.
1983
Adenosine shortens the action potential and diminishes the force of contraction in guinea-pig left atria. These effects may be brought about by the activation of a potassium conductance. This assumption is supported by voltage clamp and 42K release experiments.
On the purinergic system in rat duodenum : existence of P1and P2receptors on the smooth muscle
1990
In rat duodenum, in vitro, in the presence of atropine and guanethidine, ATP administration caused a tetrodotoxin-insensitive relaxation followed by a rebound contraction. A similar response was obtained also after electrical field stimulation (EFS) of non-adrenergic, non-cholinergic (NANC) nerves. alpha, beta-methylene-TP and theophylline antagonized the response to ATP, but they failed to affect the noradrenaline- and EFS-induced relaxation. These results suggest that P1 and P2 receptors are present in rat duodenum, but their activation is not responsible for the inhibitor effects due to the NANC nerves.
DNA-dependent DNA polymerase pattern in noninfected and herpesvirus infected rabbit kidney cells.
1973
In this paper we report on a DNA-dependent DNA polymerase produced in herpesvirus infected cells which is not present in virions. It differs from the polymerases of noninfected cells by its molecular weight as well as by its insensitivity to cytosine arabinoside triphosphate (ara-CTP).
D1 receptors play a major role in the dopamine modulation of mouse ileum contractility
2010
Since the role of dopamine in the bowel motility is far from being clear, our aim was to analyse pharmacologically the effects of dopamine on mouse ileum contractility. Contractile activity of mouse ileum was examined in vitro as changes in isometric tension. Dopamine caused a concentration-dependent reduction of the spontaneous contraction amplitude of ileal muscle up to their complete disappearance. SCH-23390, D1 receptor antagonist, which per se increased basal tone and amplitude of spontaneous contractions, antagonized the responses to dopamine, whilst sulpiride or domperidone, D2 receptor antagonists, were without effects. The application of both D1 and D2 antagonists had additive effe…
Adenosine triphosphate bioluminescence in intensive care units: Be careful with its use
2016
LETTER TO EDITOR
Inhibition of intracellular Ca2+ release by a Rho-kinase inhibitor for the treatment of ischemic damage in primary cultured rat hippocampal neurons.
2008
The effects of hydroxy fasudil, a specific Rho-kinase inhibitor, on behavior and brain neuronal activity in animal studies have been described previously. However, whether a Rho-kinase inhibitor can directly protect neurons against ischemic damage and the molecular mechanisms underlying these effects are poorly understood. The present work was designed to investigate the effect of hydroxy fasudil against oxygen-glucose deprivation (OGD) induced acute neuronal injury and the underlying mechanisms in vitro. Pretreatment with hydroxy fasudil at 5 and 10 microM could concentration-dependently improve cell viability and decrease Lactate dehydrogenase (LDH) level in extracellular solution of neur…
The phototransduction cascade in the isolated chick pineal gland revisited.
2003
It is well established that the isolated chick pineal gland is directly light sensitive and that melatonin synthesis of the gland can be inhibited by exposing the gland to light during scotophase. Since not all the steps of the phototransduction cascade have been clarified to the same extent as in the retina, we have treated isolated chick pineal glands with 90 min of light during scotophase and with drugs that affect key-components of vertebrate phototransduction, i.e., cyclic guanosine monophosphate (cGMP) phosphodiesterase 6 (PDE6), cGMP levels and cGMP-gated calcium channels. The endpoint measured was the activity of the rate-limiting enzyme of melatonin synthesis, arylalkylamine N-acet…
Is there a critical tissue oxygen tension for bioenergetic status and cellular pH regulation in solid tumors?
1996
Bioenergetic and metabolic status have been correlated with tissue oxygenation in murine fibrosarcomas (FSaII) of varying sizes (44-600 mm3). Ratios of beta-nucleoside triphosphates to inorganic phosphate (beta NTP/P) and phosphocreatine to inorganic phosphate (PCr/P(i)) ratios derived from 31P nuclear magnetic resonance spectroscopy (NMR) were positively correlated to median tissue O2 tension (pO2) values using O2-sensitive needle electrodes. pH declined during growth with intracellular acidosis being evident in tumors350 mm3. Whereas lactic acid formation greatly contributed to this decline in small and medium-sized tumors, adenosine triphosphate (ATP) hydrolysis and slowing down of the a…
Intracellular acidosis in murine fibrosarcomas coincides with ATP depletion, hypoxia, and high levels of lactate and total Pi
1994
Bioenergetic and metabolic status of murine FSaII tumours were evaluated using 31P MRS, acid extracts ('global' techniques) and quantitative bioluminescence ('microregional' assay). Data obtained from s.c. tumours of varying sizes (44-600 mm3) have been correlated with the oxygenation status evaluated using O2-sensitive needle electrodes. beta-NTP/Pi and phosphocreatine (PCr)/Pi ratios derived from 31P MRS were positively correlated to the median tissue pO2 values. pH declined during growth with intracellular acidosis being evident in tumours > 350 mm3. Whereas lactic acid formation greatly contributed to this decline in small- and medium-sized tumours, ATP hydrolysis and slowing down of th…