Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “intercellular communication”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 649 records · Page 36Linked to original sources
PubMed1989

Hydrocortisone and dexamethasone increase intercellular communication in salivary glands of Chironomus thummi larvae.

The effects of hydrocortisone (HC) and dexamethasone (DX) on intercellular electrical coupling and fluorescent dye diffusion through intercellular channels in the salivary gland cells of Chironomus thummi larvae were studied electrophysiologically. The observed electrical coupling ratios between adjacent cells in freshly excised salivary glands were widespread, ranging from 0.5 to 1.0. When HC (10 micrograms/ml) and DX (0.25 micrograms/ml) were applied to gland cells with low electrical coupling ratios (below 0.5), the coupling ratio between adjacent cells increased to 1.0 in 60 min and the resting membrane potentials were stable. The calculated junctional conductance increased fivefold, while non-junctional conductance decreased to a fifth of the starting levels. Fluorescein dye, injected into originally impermeable gland cells, was found in adjacent cells one hour after HC application. It is suggested that HC and DX acted by opening the gates of the intercellular channels.

Animals↗
PubMed2001

Spreading depolarization waves triggered by vagal stimulation in the embryonic chick brain: optical evidence for intercellular communication in the developing central nervous system.

Throughout experiments on multiple-site voltage-sensitive dye recordings of neural activity in embryonic chick brain preparations, we have found a novel type of depolarization waves which spread widely from the brainstem to the whole brain region at a rapid rate (mm/s). This depolarization wave was triggered by glutamate-mediated postsynaptic potentials and was especially correlated to N-methyl-D-aspartate receptor function. Evidence that the spreading depolarization wave is eliminated by octanol or 18beta-glycyrrhetinic acid suggests that the depolarization wave depends on functions of gap junctions. The profile obtained with Ca(2+)-imaging experiments also suggests that the propagation of the depolarization wave is accompanied by a calcium wave. These results provide new evidence for intercellular functional communication between neural cells in the vertebrate central nervous system during embryonic development.

Animals↗
PubMed1997

Oxytocin in intercellular communication in the corpus luteum.

Although oxytocin has been recognized as a product of the corpus luteum in numerous species, including nonhuman primate and women, for sometime, its precise role in luteal physiology has remained obscure. However, with the recent observations that the steroidogenic activity of the large and small cells is increased in the presence of LH when these cells are in intimate contact has led to the hypothesis that cell-to-cell communication must occur between these cells. Cell-to-cell communication is possible via several mechanisms, including paracrine/autocrine and intercellular crosstalk via gap junctions. Substantial morphological and immunohistological evidence using antibodies to gap-junction specific proteins, the connexins, indicates the presence of gap junctions in corpora lutea. Our recent studies indicate that oxytocin affects the expression of the gap-junction protein connexin-43 and that the gonadotropins are intimately involved in this action. The synthesis of oxytocin and the oxytocin receptor is influenced by the gonadotropins and locally produced prostaglandins. Oxytocin stimulates estradiol synthesis, which may affect the expression of the gap-junction protein connexin-43, allowing interaction between the large cells and small cells of the corpus luteum. With the ubiquitous presence of oxytocin and its receptor, and the presence of gap junctions in the corpora lutea of numerous species, it is concluded that oxytocin is involved in not only paracrine/autocrine interaction but also may be of significant importance in intercellular crosstalk in the corpus luteum.

Animals↗
PubMed2003

Mechanosensitivity and intercellular communication in HOBIT osteoblastic cells: a possible role for gap junction hemichannels.

Mechanically induced intercellular Ca2+ signalling was investigated in differentiated HOBIT osteoblastic cells. HOBIT cells express connexin43 clustered at the cell-to-cell boundary and display functional intercellular coupling assessed by intercellular transfer of Lucifer yellow. Mechanical stimulation of single cells, besides leading to an intracellular Ca2+ rise, induced a wave of increased Ca2+ that was radially propagated to surrounding cells. Treatment of cells with thapsigargin blocked mechanically induced signal propagation. Intercellular Ca2+ spreading was inhibited by 18alpha-glycyrrhetinic acid, demonstrating the involvement of gap junctions in signal propagation. Suramin and apyrase decreased the extent of wave propagation, suggesting that ATP-mediated paracrine stimulation contribute to cell-to-cell signalling. The functional expression of gap-junctional hemichannels was evidenced in experiments of Mn2+ quenching, extracellular dye uptake and intracellular Ca2+ release, activated by uptake of inositol 1,4,5-trisphosphate from the external medium. Gap-junctional hemichannels were activated by low extracellular Ca2+ concentrations and inhibited by 18alpha-glycyrrhetinic acid.

Adult↗
PubMed1996

Intercellular communication within the rat anterior pituitary gland: VI. Development of gap junctions between folliculo-stellate cells under the influence of ovariectomy and sex steroids in the female rat.

BACKGROUND: Farquhar (1957) initially described the folliculo-stellate cells in the rat anterior pituitary gland and found them to be located in groups around follicles throughout the anterior lobe. Soji and his co-workers have published a series of reports concerning cell-to-cell communication in the male rat hypophysis involving folliculo-stellate cells as mediated through a gap junctional network and recorded a reduction in junctional number following castration that was reversed by the administration of testosterone (Soji and Herbert, 1990, Anat. Rec., 226:342-346; Soji et al., 1990, Anat. Rec., 226:337-341). METHODS: Animals were ovariectomized at 10 days of age and separated into three groups: (1) intact control, (2) ovariectomized controls, (3) ovariectomized and given either estradiol, testosterone, or progesterone. On days 10, 20, 30, 40, and 45, the pituitary gland from animals in each group was removed and processed for ultrastructural examination. RESULTS: Gap junctions in the intact control female rats initially appeared between adjacent folliculo-stellate cells on day 20. Their numbers linearly increased until the animals reached the age of 45 days. In contrast, there was a suppression in the number of gap junctions present in the ovariectomized groups and a marked enhancement of the junctions in each of the three steroid-treated groups. CONCLUSIONS: These findings support the observations made in the male rat in which it was found that the development of gap junctions in the anterior pituitary gland of the rat is dependent in part on the presence of sex steroid hormones.

Animals↗
PubMed1988

Lactic acid inhibition of gap junctional intercellular communication in in vitro astrocytes as measured by fluorescence recovery after laser photobleaching.

Lactic acid can permeate plasma membranes, causing intracellular acidosis. Gap junctions are sensitive to pHi and can be reversibly uncoupled by weak acids. In this study, dye coupling between in vitro astrocytes, presumably mediated by gap junctions, was measured in the absence and presence of lactic acid. Fluorescence recovery after laser photobleaching (gap-FRAP analysis) was used to measure dye coupling. Astrocytes bathed in Eagle's minimum essential medium (EMEM) with lactic acid, pHo 5.5-6, showed no difference in their dye coupling (mean recovery of fluorescence 30%) when compared to control astrocytes (mean recovery of fluorescence 26%). However, 24 mM lactic acid in EMEM, pHo 4.5, decreased dye coupling (mean recovery of fluorescence 2.0%). This effect occurred within 5 min of treatment. When lactic acid-EMEM, pH 4.5, was removed from astrocytes after 30 min and the cells were incubated in EMEM for 24 hr, decreased coupling was not reversed (mean recovery 4.0%). When lactic acid-treated astrocytes were incubated in EMEM for 48 hr, the mean recovery of fluorescence increased to 15% (i.e., 42% of the recovery seen in controls). These observations suggest that brief exposure to high concentrations of lactic acid can have immediate and long-lasting effects on glial gap junctional communication. Under pathological circumstances, such a sequence could be initiated, and this might impair astrocytic control of the central nervous system microenvironment mediated by spatial buffering.

Animals↗
PubMed1992

A relationship between gap junction-mediated intercellular communication and the in vitro developmental capacity of murine embryonic stem cells.

Two metabolic cooperation-deficient variants, 1P9 and 2P2[1], have been isolated from the embryonic stem cell line B2B2. Characterization of these cell lines has shown that both variants are severely restricted with respect to embryoid body differentiation capacity while a revertant isolated from 1P9, designated 2H4, has its differentiation phenotype restored to a level comparable with that of the parent line. These results are interpreted as indicating that the metabolic cooperation deficiency and the restricted differentiation phenotype of 1P9 are causally related. A revertant isolated from 2P2[1], designated H19, remains severely restricted with regard to embryoid body differentiation, suggesting that in these lines a secondary event deleterious to differentiation, but unrelated to metabolic cooperation, has taken place.

Animals↗
PubMed2002

Novel intercellular communication system in Escherichia coli that confers antibiotic resistance between physically separated populations.

AIMS: To determine whether intercellular signalling can occur between physically separated populations of Escherichia coli. METHODS AND RESULTS: Intercellular signalling between physically discrete populations of E. coli BL21 was analysed in bi-partite Petri dishes. Transfer of a growth-promoting signal resulted in induction of resistance to the antibiotic ampicillin. Optimal expression of the signal occurred when the signalling population was established as a bacterial lawn for 24 h. This represented an entry into the stationary phase of growth, as indicated by the expression profile of the RNA polymerase subunit sigma38 (sigmaS; sigma S). The growth-promoting effect was also observed when E. coli DH5alpha (luxS-) was used as the signalling population. Preventing passage of air between the two populations resulted in a complete cessation of the growth-promoting effect. CONCLUSIONS: A growth-promoting signal occurs between physically separated cultures of E. coli. The exact nature of the signal remains to be determined but does not involve the production of autoinducer-2 from the luxS gene. Signal transmission is likely to involve airborne transfer of a signal species. SIGNIFICANCE AND IMPACT OF THE STUDY: Intercellular signalling systems exist in bacteria that enable antibiotic resistance to be conferred between physically separated populations.

Air↗
PubMed1998

Recent advances in biology: intercellular communication and quorum sensing in micro-organisms.

N-acyl-L-homoserine lactones are involved as intercellular signalling agents controlling a wide range of physiological responses in Gram-negative bacteria. They function especially in vibrios, pseudomonads and erwinias as well as in Rhizobium and Agrobacterium spp, particularly where the bacteria are in symbiotic or parasitic relationships with higher organisms. Several Gram-negatives, such as Escherichia coli, do not, however, appear to produce or respond to AHLs and they may have other intercellular signalling molecules. The present review reports that several stress related responses in E. coli can be induced by supernatant fluids from cultures which have already induced the response. In some cases at least, the active agents in the supernatant fluids are proteins rather than AHLs.

Cell Division↗
PubMed1990

Intercellular communication within the rat anterior pituitary gland. I. Postnatal development and changes after injection of luteinizing hormone-releasing hormone (LH-RH) or testosterone.

The postnatal development of gap junction formation and cell-to-cell communication were investigated in male rats from 10 through 40 days of age. These junctions initially appeared between adjacent folliculo-stellate cells on day 20. Their numbers increased until the animals reached the age of 40 days, when their frequency reached a level that resembled that found in adults. The ontogeny of these junctions was examined in rats treated with luteinizing hormone releasing hormone (LH-RH) or testosterone. The two hormones were injected for 1 week into rats aged 3, 13, 23, or 33 days. The appearance of gap junctions was accelerated in a similar fashion by LH-RH and testosterone, with their formation and numbers being advanced by 10 days over that observed in the untreated controls. The results suggest a role for the gonadal steroid hormones in the formation of gap junctions in the rat hypophysis.

Animals↗