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1.
Spreading depression (SD) was elicited in rats anesthetized with pentobarbital by a train of 8 electrical pulses (0.1 ms, 10 Hz) applied to parietal cortex. Local application of 50 micrograms of D-ala2-metenkephalinamide (DAME) on the stimulated area evoked one or two SD waves followed by an increase of SD threshold from 40 V to 90 V. This effect could be partly prevented by naloxone (1 mg/kg i.p.) and reversed by local application of 4-aminopyridine (10(-3) M, 2 microliters), which reduced SD threshold to 5 and 20 V in normal and DAME-treated cortex, respectively. It is argued that DAME exerts an inhibitory effect on cortical neurons and that the initial SD facilitation is due to initial blockade of inhibitory neurons in the superficial cortical layers. 相似文献
2.
Zusammenfassung Vorübergehende ein- oder beidseitige funktionelle Dekortikation mittels «spreading depression» ergibt bei elektrischer Reizung des Tegmentums oder Hypothalamus einen Schwellenanstieg des Weckeffektes. Die Reaktionsunterschiede der Hirnteile werden über die theta-Aktivität im Hippokampus beurteilt. 相似文献
3.
J. A. Fernandez-Lopez I. Subirade Y. Fernandez P. Deltour A. Periquet S. Mitjavila 《Cellular and molecular life sciences : CMLS》1993,49(10):854-858
Direct membrane injury by CCl4, in situations excluding metabolic activation, was evaluated in saponin-permeabilized hepatocytes and in microsomes by measuring immediate Ca2+ efflux. A good correlation appears between the Ca2+ efflux and the level of CCl4 in the membrane and also the variations in fluidity. Mixtures of CCl4 with water-soluble vehicles were used to improve the dispersion of CCl4 in the medium. The mixtures varied in their ability to elicit the membrane effects of CCl4. The performance of ethanol and, to a lesser degree, other alcohols, suggests the existence of a water stable structural organization between CCl4 and these amphiphilic vehicles, facilitating the transfer of CCl4 to the membrane. 相似文献
4.
Using a newly developed microcalorimetric approach to assess the rate of energy expenditure for intracellular [Ca2+] homeostasis in isolated muscles at rest, we found this was lower inmdx than in control mouse muscles, by 62% and 29% in soleus and extensor digitorum longus, respectively. Differences in total and Ca2+-dependent rates of specific heat production betweenmdx and control were enhanced during sustained, KCl-induced stimulation of energy dissipation. These results suggest that the low sacroplasmic energy status of dystrophic muscles is not due to any excessive energy expenditure for intracellular [Ca2+] homeostasis. 相似文献
5.
É. Rónai L. Mészáros Gy. Benkő I. Horváth 《Cellular and molecular life sciences : CMLS》1984,40(12):1375-1376
Summary Succinate inhibits NADPH-dependent lipid peroxidation of liver mitochondria. This effect of succinate decreased 12 h after whole-body60Co-gamma irradiation, depending on the dose of irradiation. 相似文献
6.
S. Ebashi 《Cellular and molecular life sciences : CMLS》1985,41(8):978-981
7.
N. Manabe Y. Imai H. Ohno Y. Takahagi M. Sugimoto H. Miyamoto 《Cellular and molecular life sciences : CMLS》1996,52(7):647-651
The porcine antral follicles, 3–6 mm in diameter, were dissected from the ovaries of mature pigs, and then granulosa and cumulus cells were isolated from each follicle. In atretic follicles, high activity of neutral Ca2+/Mg2+-dependent endonuclease and DNA ladder formation, estimated by electrophoresis, were noted in granulosa cells but not in cumulus cells. Extremely low activity of the endonuclease and no DNA ladder formation were observed in both types of cells obtained from healthy follicles. Moreover, apoptotic cells were observed histochemically among granulosa cells only. A good correlation (r=0.987) between the endonuclease activity of granulosa cells and the progesterone/estradiol ratio of follicular fluid in each follicle was found. These results suggest that apoptosis occurs in granulosa cells but not cumulus cells in the atretic antral follicles in pigs. 相似文献
8.
9.
Summary Fructose-1,6-diphosphate counteracts potassium ejection and proton uptake induced in rat red blood cells by valinomycin and an uncoupler. The effect on potassium ejection is reduced in the presence of ouabain and divalent cations. 相似文献
10.
F. Wuytack L. Raeymaekers R. Casteels 《Cellular and molecular life sciences : CMLS》1985,41(7):900-905
Summary A calmodulin stimulated Ca2+-transport ATPase which has many of the characteristics of the erythrocyte type Ca2+-transport ATPase has been purified from smooth muscle. In particular, the effect of calmodulin on these transport enzymes is mimiced by partial proteolysis and antibodies against erythrocyte Ca2+-transport ATPase also bind to the smooth muscle (Ca2++Mg2+)ATPase. A correlation between the distribution of the calmodulin stimulated (Ca2++Mg2+)ATPase and (Na++K+)ATPase activities in smooth muscle membranes separated by density gradient centrifugation suggests a plasmalemmal distribution of this (Ca2++Mg2+)ATPase. A phosphoprotein intermediate in smooth muscle which strongly resembles the corresponding phosphoprotein in sarcoplasmic reticulum of skeletal muscle may indicate the presence in smooth muscle of a similar type of Ca2+-transport ATPase. 相似文献
11.
Selective pharmacological Na+/H+ exchange (NHE) inhibitors were used to identify functional NHE isoforms in human small intestinal enterocytes (Caco-2) and to distinguish between direct and indirect effects on transport via the intestinal di/tripeptide transporter hPepT1. The relative potencies of these inhibitors to inhibit 22Na+ influx identifies NHE3 and NHE1 as the apical and basolateral NHE isoforms. The Na+-dependent (NHE3-sensitive) component of apical dipeptide ([14C] Gly-Sar) uptake was inhibited by the selective NHE inhibitors with the same order of potency observed for inhibition of apical 22Na+ uptake. However, 5-(N-ethyl-N-isopropyl) amiloride (EIPA) also reduced [14C]Gly-Sar uptake in the absence of Na+ and this inhibition was concentration and pH (maximal at pH 5.5) dependent. NHE3 inhibition by S1611 and S3226 modulates dipeptide uptake indirectly by reducing the transapical driving force (H+ electrochemical gradient). EIPA (at 100 μM) has similar effects, but at higher concentrations (>200 μM) also has direct inhibitory effects on hPepT1.Received 28 February 2005; received after revision 20 April 2005; accepted 20 May 2005 相似文献
12.
Summary Potassium movements were monitored in liver mitochondria from control and alloxan diabetic rats with a cationic electrode. There was net accumulation of K+ after Ca2+ addition to the mitochondria with the diabetic but not with the control. 相似文献
13.
Summary The role of Ca2+ in secretagogue-induced insulin release is documented not only by the measurements of45Ca fluxes in pancreatic islets, but also, by direct monitoring of cytosolic free Ca2+, [Ca2+]i. As demonstrated, using the fluorescent indicator quin 2, glyceraldehyde, carbamylcholine and alanine raise [Ca2+]i in the insulin secreting cell line RINm5F, whereas glucose has a similar effect in pancreatic islet cells. The regulation of cellular Ca2+ homeostasis by organelles from a rat insulinoma, was investigated with a Ca2+ selective electrode. The results suggest that both the endoplasmic reticulum and the mitochondria participate in this regulation, albeit at different Ca2+ concentrations. By contrast, the secretory granules do not appear to be involved in the short-term regulation of [Ca2+]i. Evidence is presented that inositol 1,4,5-trisphosphate, which is shown to mobilize Ca2+ from the endoplasmic reticulum, is acting as an intracellular mediator in the stimulation of insulin release. 相似文献
14.
Summary Equivalent spaces of42K were measured in fragments of the submandibular gland of 1-, 7-, 14- and 21-day-old and adult rats in the absence and presence of carbachol and the transport inhibitors ouabain and furosemide. The results indicate that the42K space was increased by carbachol in an ouabain-sensitive manner at all ages studied and that part of the secretagogue-stimulated K uptake occurred by way of a furosemide-sensitive transport system in the latter part of the postnatal period and in the adult. 相似文献
15.
J. Kobayashi M. Ishibashi H. Nakamura Y. Hirata T. Yamasu T. Sasaki Y. Ohizumi 《Cellular and molecular life sciences : CMLS》1988,44(9):800-802
Summary A novel sphingosine derivative, symbioramide, has been isolated from the laboratory-cultured dinoflagellateSymbiodinium sp. as a sarcoplasmic reticulum (SR) Ca2+-ATPase activator, and its structure elucidated to be1 on the basis of spectral and chemical means.Acknowledgments. We thank Ms M. Hamashima and Ms A. Muroyama for their technical assistance. 相似文献
16.
T. Murayama Y. Ohizumi H. Nakamura T. Sasaki J. Kobayashi 《Cellular and molecular life sciences : CMLS》1989,45(9):898-899
Summary A new cyclic peroxide, plakorin, which is a potent sarcoplasmic reticulum (SR) Caa+-ATPase activator has been isolated from the Okinawan marine spongePlakortis sp., its structure was elucidated on the basis of spectral data.Acknowledgments. We thank Ms M. Hamashima and Ms A. Muroyama for their technical assistance. 相似文献
17.
T. Nasu 《Cellular and molecular life sciences : CMLS》1994,50(8):717-720
In the presence of Zn2+ (0.3 mM), carbachol (10–6 M) or histamine (10–5 M) induced the phasic response in guinea-pig taenia caeci while the tonic response was markedly inhibited. However, when the muscles were kept in Zn2+-containing medium following the first stimulation with either carbachol or histamine, neither application of carbachol nor of histamine elicited another phasic contraction. Caffeine (25 mM) did not induce contraction in the presence of Zn2+. After the washing out of caffeine in the presence of Zn2+, however, the muscle did then develop the phasic response on the application of carbachol or histamine. In conclusion, Zn2+ did not affect the carbachol or histamine-induced Ca2+ release from the storage sites. However, when Zn2+ was continuously present, Ca2+ was not supplied to the storage sites. Furthermore, carbachol and histamine mobilized a common cellular Ca2+ store, but they activated Ca2+ release channels different from the ones activated by caffeine in the Ca2+ storage sites. 相似文献
18.
C.-J. Chang P.-H. Yin D.-M. Yang C.-H. Wang W.-Y. Hung C.-W. Chi Y.-H. Wei H.-C. Lee 《Cellular and molecular life sciences : CMLS》2009,66(10):1755-1765
The aim of this study was to investigate the contribution of mitochondrial dysfunction to chemoresistance and migration of
hepatoma cells. We found that inhibition of mitochondrial respiration and mitochondrial DNA (mtDNA) depletion resulted in
induction of amphiregulin (AR) expression in HepG2 cells. Upon oligomycin treatment of HepG2 cells, the cytosolic Ca2+ was significantly raised after 30 min, and the intracellular level of reactive oxygen species (ROS) was elevated 2.2-fold
after 4 h. Moreover, the condition medium of oligomycin-treated HepG2 cells was found to stimulate the migration of SK-Hep-1
cells. On the other hand, oligomycin-induced cisplatin-resistance and cell migration of HepG2 cells were attenuated by AR-specific
RNA interference (#L-017435, Dharmacon) and a neutralizing antibody (MAB262, R&D Systems), respectively. Together, these findings
suggest that mitochondrial dysfunction induced Ca2+ mobilization, and ROS overproduction, which modulated the chemo-resistance and migration of hepatoma cells through the induction
and activation of AR.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Y.-H. Wei, H.-C. Lee: These authors contribute equally to this work.
Received 02 December 2008; received after revision 16 March 2009; accepted 17 March 2009 相似文献
19.
Summary It is reported that Ca2+-induced discharge of in situ nematocytes of acontia ofCalliactis parasitica can occur by cell-to-cell transmission along the acontial filament at a speed that averages 9.8·10–3 cm–1. The discharge is preceded by protrusion of nematocytes that proceeds along the acontium at a slightly higher speed. 相似文献
20.
Cellular pathology induced by snake venom phospholipase A2 myotoxins and neurotoxins: common aspects of their mechanisms of action 总被引:3,自引:0,他引:3
Montecucco C Gutiérrez JM Lomonte B 《Cellular and molecular life sciences : CMLS》2008,65(18):2897-2912
A large variety of snake toxins evolved from PLA2 digestive enzymes through a process of ‘accelerated evolution’. These toxins have different tissue targets, membrane receptors
and mechanisms of alteration of the cell plasma membrane. Two of the most commonly induced effects by venom PLA2s are neurotoxicity and myotoxicity. Here, we will discuss how these snake toxins achieve a similar cellular lesion, which
is evolutionarily highly conserved, despite the differences listed above. They cause an initial plasma membrane perturbation
which promotes a large increase of the cytosolic Ca2+ concentration leading to cell degeneration, following modes that we discuss in detail for muscle cells and for the neuromuscular
junction. The different systemic pathophysiological consequences caused by these toxins are not due to different mechanisms
of cell toxicity, but to the intrinsic anatomical and physiological properties of the targeted tissues and cells.
Received 05 March 2008; received after revision 08 April 2008; accepted 29 April 2008 相似文献