Presence of task-1 channel in the laryngeal mucosa in the newborn lamb.

Nearly 40 potassium channels have been described in respiratory epithelial cells. Of these are found several members of the 4-transmembrane domain, 2-pore K(+) channel family (K2P family), namely Twik-1 and -2, Trek-1 and -2, Task-2, -3, and -4, Thik-1, and KCNK7. The aim of this study was to verify whether the Twik-related acid-sensitive K(+) channel, subtype 1 (Task-1) (also known as KCNK3), is present in the laryngeal mucosa in the newborn lamb.

TRPV-5 mediates a receptor activator of NF-kappaB (RANK) ligand-induced increase in cytosolic Ca2+ in human osteoclasts and down-regulates bone resorption.

Most of the signaling effectors located downstream of receptor activator of NF-kappaB (RANK) activation are calcium-sensitive. However, the early signaling events that lead to the mobilization of intracellular calcium in human osteoclasts are still poorly understood. The Ca(2+)-sensitive fluorescent probe Fura2 was used to detect changes in the intracellular concentration of Ca(2+) ([Ca(2+)](i)) in a model of human osteoclasts.

In vivo intravital endoscopic confocal fluorescence microscopy of normal and acutely injured rat lungs.

We present a new lung imaging technique based on endoscopic confocal fluorescence microscopy (ECFM), which is a new method that is able to provide cellular and structural assessment of living tissue using a small confocal probe in direct contact with the visceral pleura. To observe distal airspace structure and cellular condition in normal and injured lungs (hyperoxic and bleomycin challenged), we used fluorescent-specific marker contrast and ECFM. Alveolar space ECFM with spectral analyses were performed at 488-nm excitation using FITC-labeled markers or naturally fluorescent dyes.

From integrative signalling to metabolic disorders.

The adrenal cortex undergoes constant dynamic structural changes, a key element in ensuring integrative functionality of the gland. Studies have shown that the cellular environment can modulate cell functions such as proliferation and steroid secretion. For example, 3-day treatment with angiotensin II promotes protein synthesis with a concomitant decrease in proliferation of glomerulosa cells, when cultured on fibronectin, but not on collagen IV or laminin.

In adrenal glomerulosa cells, angiotensin II inhibits proliferation by interfering with fibronectin-integrin signaling.

Angiotensin II (Ang II), through the Ang II type 1 receptor subtype, inhibits basal proliferation of adrenal glomerulosa cells by inducing the disruption of actin stress fiber organization. This effect is observed in cells cultured on plastic or on fibronectin. The aim of the present study was to investigate how Ang II may interfere with extracellular matrix/integrin signaling.

Angiotensin II type 2 receptor stimulation increases the rate of NG108-15 cell migration via actin depolymerization.

Angiotensin II (Ang II) has been reported to induce migration in neuronal cell types. Using time-lapse microscopy, we show here that Ang II induces acceleration in NG108-15 cell migration. This effect was antagonized by PD123319, a selective AT2 receptor antagonist, but not by DUP753, a selective AT1 receptor antagonist, and was mimicked by the specific AT2 receptor agonist CGP42112.

The growth-promoting effects of angiotensin II in adrenal glomerulosa cells: an interactive tale.

The zona glomerulosa of the adrenal cortex is well-known for its high level of proliferation, compared to the adjacent zona fasciculata, both in in vivo and in vitro conditions. Angiotensin II (Ang II) is a potent growth factor for glomerulosa cells, appearing as a proliferative factor in vivo, under sodium-deficient diet conditions, as well as in vitro, in studies conducted with whole zona glomerulosa. However, in cells maintained in primary culture for 3 days, Ang II rather promotes cellular hypertrophy with a concomitant arrest in basal cell proliferation.

Expression of extracellular matrix proteins and integrins in rat adrenal gland: importance for ACTH-associated functions.

The expression of main extracellular matrix (ECM) and their integrins were studied in the adult rat adrenal gland. Collagen I, IV (CI, CIV), laminin (LN) and fibronectin (FN) expression was observed surrounding each glomerulosa cell and as long fibrils between the cords of fasciculata cells. In the medulla, FN was present around chromaffin cells or bordering blood vessels.

An oxidized metabolite of linoleic acid increases intracellular calcium in rat adrenal glomerulosa cells.

EKODE, an epoxy-keto derivative of linoleic acid, was previously shown to stimulate aldosterone secretion in rat adrenal glomerulosa cells. In the present study, we investigated the effect of exogenous EKODE on cytosolic [Ca(2+)] increase and aimed to elucidate the mechanism involved in this process. Through the use of the fluorescent Ca(2+)-sensitive dye Fluo-4, EKODE was shown to rapidly increase intracellular [Ca(2+)] ([Ca(2+)](i)) along a bell-shaped dose-response relationship with a maximum peak at 5 microM.

Involvement of protein kinase C alpha (PKC alpha) in the early action of angiotensin II type 2 (AT2) effects on neurite outgrowth in NG108-15 cells: AT2-receptor inhibits PKC alpha and p21ras activity.

The aim of the present study was to investigate whether protein kinase C (PKC) isoforms may be among the putative candidates implicated in the primary effects of the Ang II type 2 (AT2) receptor. Western blot analyses revealed the presence of PKC alpha,epsilon, iota, and zeta in NG108-15 cells. After a 3-d treatment with 3 nm Gö6976, a specific inhibitor of classical PKC isoforms, cells were characterized by the presence of one elongated process similar to that observed after treatment with Ang II or with CGP42112, a selective AT2 receptor agonist.

Human melanocortin receptor 2 expression and functionality: effects of protein kinase A and protein kinase C on desensitization and internalization.

The aim of this study was to investigate the short-term regulation of the ACTH receptor human (h) melanocortin receptor 2 (MC2R) by transfection of a c-Myc-tagged hMC2R in the M3 cell line and assess its membrane expression by indirect immunofluorescence. Stimulation with ACTH induced production of cAMP with EC(50) values ranging from 7.6-11.

Angiotensin II stimulates protein synthesis and inhibits proliferation in primary cultures of rat adrenal glomerulosa cells.

Angiotensin II (Ang II) is one of the most important stimuli of rat adrenal glomerulosa cells. The aim of the present study was to investigate whether Ang II can stimulate cell proliferation and/or hypertrophy and investigate pathways and intracellular targets. A 3-d treatment with Ang II (5-100 nm), through the Ang II type 1 receptor subtype, abolished cell proliferation observed in control cells but increased protein synthesis.

Low-affinity neurotensin receptor (NTS2) signaling: internalization-dependent activation of extracellular signal-regulated kinases 1/2.

The role and signaling properties of the low-affinity neurotensin receptor (NTS2) are still controversial. In particular, it is unclear whether neurotensin acts as an agonist, inverse agonist, or antagonist at this site. In view of the growing evidence for a role of NTS2 in antinociception, the elucidation of the pharmacological and coupling properties of this receptor is particularly critical.

Protein kinase C inhibits the transplasma membrane influx of Ca2+ triggered by 4-aminopyridine in Jurkat T lymphocytes.

4-aminopyridine (4AP) is a general blocker of voltage-dependent K+ channels. This pyridine derivative has also been shown to inhibit T cell proliferation, to modulate immune responses and to alleviate some of the symptoms associated with neurological disorders such as multiple sclerosis, myasthenia gravis and Alzheimer's disease. 4AP triggers a Ca2+ response in lymphocytes, astrocytes, neurons and muscle cells but little is known about the regulation of the 4AP response in these cells.

20-hydroxyeicosatetraenoic acid (20-HETE) activates mouse TRPC6 channels expressed in HEK293 cells.

In the present study, we show that the eicosanoid compound, 20-hydroxyeicosatetraenoic acid (20-HETE), an important arachidonic acid metabolite, activates mouse TRPC6 in a stable, overexpressing HEK293 cell line, Hek-t6.11. Application of 20-HETE rapidly induced an inward, non-selective current in whole-cell recordings, which was inhibited by N-methyl-d-glucamine, 1.

Mechanism of action of ACTH: beyond cAMP.

ACTH is the major regulator of adrenal cortex function, having acute and chronic effects on steroid synthesis and secretion. The precise molecular mechanisms by which ACTH stimulates steroid synthesis and secretion, as well as cell hypertrophy, survival, and migration are still poorly understood. Several studies have shown that ACTH action is mediated not only by cyclic adenosine monophosphate (cAMP), but also by calcium (Ca(2+)), both interacting closely through positive feedback loops to enhance steroid secretion.

20-HETE inotropic effects involve the activation of a nonselective cationic current in airway smooth muscle.

20-Hydroxyeicosatetraenoic acid (20-HETE) controls several mechanisms such as vasoactivity, mitogenicity, and ion transport in various tissues. Our goal was to quantify the effects of 20-HETE on the electrophysiological properties of airway smooth muscle (ASM). Isometric tension measurements, performed on guinea pig ASM, showed that 20-HETE induced a dose-dependent inotropic effect with an EC50 value of 1.

Connection between integrins and cell activation in rat adrenal glomerulosa cells: a role for Arg-Gly-Asp peptide in the activation of the p42/p44(mapk) pathway and intracellular calcium.

Integrins are responsible for adhesion and activation of several intracellular cascades. The present study was aimed at determining whether the interaction between fibronectin and integrins could generate pathways involved in physiological functions of rat adrenal glomerulosa cells. Immunofluorescence studies and adhesion assays showed that fibronectin was the best matrix in promoting the formation of focal adhesion.

Differential recruitment of alpha2beta1 and alpha4beta1 integrins to lipid rafts in Jurkat T lymphocytes exposed to collagen type IV and fibronectin.

Collagen type IV (CnIV) and fibronectin (Fn) were used as ligands to study the distribution of alpha(2)beta(1) and alpha(4)beta(1) integrins in low-density, detergent-resistant microdomains (DRM) of Jurkat lymphocytes. CnIV-coated microspheres induced (optical trapping) the redistribution of GM(1)-associated fluorescence from the cell periphery to the area of contact. This was not observed in cells treated with beta-methyl cyclodextrin (MCD).

Cyclic AMP-independent involvement of Rap1/B-Raf in the angiotensin II AT2 receptor signaling pathway in NG108-15 cells.

The angiotensin II (Ang II) type 2 (AT(2)) receptor is an atypical seven-transmembrane domain receptor. Controversy surrounding this receptor concerns both the nature of the second messengers produced as well as its associated signaling mechanisms. Using the neuronal cell line NG108-15, we have reported previously that activation of the AT(2) receptor induced morphological differentiation in a p21(ras)-independent, but p42/p44(mapk)-dependent mechanism.

PAC1 receptor activation by PACAP-38 mediates Ca2+ release from a cAMP-dependent pool in human fetal adrenal gland chromaffin cells.

Previous studies have shown that human fetal adrenal gland from 17- to 20-week-old fetuses expressed pituitary adenylate cyclase-activating polypeptide (PACAP) receptors, which were localized on chromaffin cells. The aim of the present study was to identify PACAP receptor isoforms and to determine whether PACAP can affect intracellular calcium concentration ([Ca(2+)](i)) and catecholamine secretion. Using primary cultures and specific stimulation of chromaffin cells, we demonstrate that PACAP-38 induced an increase in [Ca(2+)](i) that was blocked by PACAP (6-38), was independent of external Ca(2+), and originated from thapsigargin-insensitive internal stores.

Nitric oxide and cyclic GMP are involved in angiotensin II AT(2) receptor effects on neurite outgrowth in NG108-15 cells.

In their undifferentiated state, NG108-15 cells express only the angiotensin II (Ang II) type 2 receptor (AT(2)). We have previously shown that Ang II induced neurite outgrowth of NG108-15 cells, a process involving sustained activation of p42/p44(mapk) activity. We have also shown that Ang II stimulates nitric oxide (NO) production.