The inhibitor of volume-regulated anion channels DCPIB activates TREK potassium channels in cultured astrocytes.

BACKGROUND AND PURPOSE: The ethacrynic acid derivative, 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid (DCPIB) is considered to be a specific and potent inhibitor of volume-regulated anion channels (VRACs). In the CNS, DCPIB was shown to be neuroprotective through mechanisms principally associated to its action on VRACs. We hypothesized that DCPIB could also regulate the activity of other astroglial channels involved in cell volume homeostasis. EXPERIMENTAL APPROACH: Experiments were performed in rat cortical astrocytes in primary culture and in hippocampal astrocytes in situ. The effect of DCPIB was evaluated by patch-clamp electrophysiology and immunocytochemical techniques. Results were verified by comparative analysis with recombinant channels expressed in COS-7 cells. KEY RESULTS: In cultured astrocytes, DCPIB promoted the activation of a K(+) conductance mediated by two-pore-domain K(+) (K(2P) ) channels. The DCPIB effect occluded that of arachidonic acid, which activates K(2P) channels K(2P) 2.1 (TREK-1) and K(2P) 10.1 (TREK-2) in cultured astrocytes. Immunocytochemical analysis suggests that cultured astrocytes express K(2P) 2.1 and K(2P) 10.1 proteins. Moreover, DCPIB opened recombinant K(2P) 2.1 and K(2P) 10.1 expressed in heterologous system. In brain slices, DCPIB did not augment the large background K(+) conductance in hippocampal astrocytes, but caused an increment in basal K(+) current of neurons. CONCLUSION AND IMPLICATIONS: Our results indicate that the neuroprotective effect of DCPIB could be due, at least in part, to activation of TREK channels. DCPIB could be used as template to build new pharmacological tools able to increase background K(+) conductance in astroglia and neuronal cells.

Extrinsic afferents supplying the ovine duodenum and ileum.

The study aimed at establishing the distribution of primary sensory neurons by means of retrograde tracers Diamidino Yellow (DY) and Fast Blue (FB) injected into both the sheep duodenum and ileum, respectively. Many DY-labelled cells were found in both the distal vagal ganglia (DVG) and the spinal ganglia (SG) from T9-L3; on the contrary, the majority of the FB-labelled cells were found in the SG. In the SG, a double immunofluorescence stain was used to reveal Nitric Oxide Synthase-Immunoreactivity (NOS-IR) in association with: substance P (SP), calcitonin gene-related peptide (CGRP), neurofilament 200kDa (NF) and isolectin B(4) (IB4). The labelled neurons, both DY and FB generally ranged in size from medium to large. The majority of the SG duodenal projections were NOS negative; the majority of the SG ileal afferent neurons expressed NOS-IR. Both DY and FB NOS-IR neurons often co-localized IB4, CGRP and SP, but rarely NF.

A tryptophan-enriched diet improves feed intake and growth performance of susceptible weanling pigs orally challenged with Escherichia coli K88.

We tested the effect of Trp addition to a standard weaning diet and oral challenge with enterotoxigenic Escherichia coli K88 (ETEC) on growth and health of piglets susceptible or nonsusceptible to the intestinal adhesion of ETEC. Sixty-four pigs weaned at 21 d of age were divided into 3 groups based on their ancestry and BW: a control group of 8 pigs fed a basal diet (B), the first challenged group of 28 pigs fed B diet (BCh), and the second challenged group of 28 pigs fed a diet with Trp (TrpCh). The Trp diet was produced by the addition of 1 g of l-Trp/kg to the basal diet. On d 5, pigs were orally challenged with 1.5 mL suspension containing 10(10) cfu ETEC/mL or placebo, and killed on d 9 or 23. Based on in vitro villus adhesion assay, the pigs (except the B group) were classified as susceptible (s(+)) or nonsusceptible (s(-)) to the intestinal ETEC adhesion. Thus, after the challenge, treatments were B, BChs(-), BChs(+), TrpChs(-), and TrpChs(+). Pigs susceptible to ETEC were 50.0% in the BChs(+) group (3 pigs lost included) and 46.4% in the TrpChs (+) group (1 pig lost included). During the first 4 d after challenge, the challenge reduced ADG (P < 0.05), and this reduction was greater in susceptible pigs (P < 0.05) than nonsusceptible ones. Tryptophan increased ADG and feed intake in susceptible pigs (P < 0.05) from challenge to d 4, but not thereafter. Tryptophan supplementation did not improve the fecal consistency and did not reduce the number of pigs positive for ETEC in feces on d 4 after the challenge. The K88-specific immunoglobulin A activity in blood serum tended to be greater in challenged pigs (P = 0.102) and was not affected by the addition of Trp. Villous height was affected by the addition of Trp and challenge in different ways, depending on the site of small intestine. The need to consider the phenotype for the adhesion of the ETEC in studies with different supply of Trp was clearly evident. When compared with practical weaning standard diets, Trp supplementation allowed susceptible pigs to partially compensate for the effects of ETEC challenge by increasing feed intake and maintaining an adequate BW growth. This is of practical importance for the formulation of diets for pigs selected for lean growth because of the presence of an association between this trait and the susceptibility to the intestinal adhesion of ETEC.

Transplantation activity in the Organizzazione Centro-Sud Trapianti: a retrospective study from 1999 to March 2004.

BACKGROUND: The Organizzazione Centro-Sud Trapianti (OCST) was set up in 1998 to coordinate the organ procurement and transplantation activity of 9 italian regions (Abruzzo, Basilicata, Calabria, Campania, Lazio, Molise, Sardinia, Sicily, and Umbria), each referring to a local Regional Transplant Center. The aim of the present study was to estimate organ donation and transplantation rates in the OCST from 1999 to March 2004. MATERIALS AND METHODS: A retrospective study of organ donors and transplantation activity in the OCST during the study period was performed, pointing out donor epidemiological data, such as age and sex ratio, causes of death, reasons for discarding, and transplantation rates. Donors reported to the OCST were divided into 6 groups: A (October 1998-December 1999), B (2000), C (2001), D (2002), E (2003), and F (January-March 2004). RESULTS: From 1999 to March 2004, 2272 potential donors were reported to the OCST. The nonharvested donors rate increased up to 52% (Group F), which was lower than the previous period (Group E, 64%), but higher than in 1999 (Group A, 43%). The major contributing factor was family opposition, which was 38% in 2002 and 41% in 2003. CONCLUSIONS: The introduction of the OCST into the field of organ transplantation has yielded an increase in organ donation and transplantation activity within the regions that set it up from 1999-2003. This trend is a consequence of the growth of reported donors from the intensive care unit, which grew 12.7% from 2002 to 2003. From the data analysis of the first months of 2004, we expect confirmation of this trend.