calcimycin and Diarrhea

Zinc is a useful addition to oral rehydration therapy for acute diarrhoea. We have assessed the mechanism of its epithelial antisecretory action when intestinal epithelial tight junctions were pharmacologically opened.. Rat isolated ileal and colonic mucosae were mounted in Ussing chambers and exposed to ZnSO(4) (Zn(2+) ) in the presence of secretagogues and inhibition of short circuit current (I(sc) ) was measured.. Pre-incubation with basolateral but not apical Zn(2+) reduced I(sc) stimulated by forskolin, carbachol and A23187. In the presence of the tight junction-opener, cytochalasin D, antisecretory effects of apically-applied Zn(2+) were enabled in colon and ileum. The apparent permeability coefficient (P(app) ) of Zn(2+) was increased 1.4- and 2.4-fold across rat ileum and colon, respectively, by cytochalasin D. Basolateral addition of Zn(2+) also reduced the I(sc) stimulated by nystatin in rat colon, confirming K channel inhibition. In comparison with other inhibitors, Zn(2+) was a relatively weak blocker of basolateral K(ATP) and K (Ca2+) channels. Exposure of ileum and colon to Zn(2+) for 60 min had minimal effects on epithelial histology.. Antisecretory effects of Zn(2+) on intestinal epithelia arose in part through nonselective blockade of basolateral K channels, which was enabled when tight junctions were open.

Topics: Animals; Antidiarrheals; Calcimycin; Carbachol; Colforsin; Colon; Cytochalasin D; Diarrhea; Electricity; Ileum; Intestinal Mucosa; Intestinal Secretions; Ionophores; Ions; Male; Nystatin; Permeability; Potassium Channel Blockers; Potassium Channels; Rats; Rats, Wistar; Tight Junctions; Zinc; Zinc Sulfate

Allergic reactions to food can involve diarrhea, vomiting, nausea and abnormal pain. PG102 has previously been shown to control various factors involved in allergy pathogenesis, including IgE and various Th1 and Th2 cytokines, in vivo as well as in vitro [Park EJ, et al.: J Allergy Clin Immunol 2005;116:1151-1157; Park EJ, et al.: J Invest Dermatol 2007;127:1154-1160]. These data indicate that PG102 might have antiallergic effects on allergic diarrhea. Here, we investigated whether PG102 could prevent allergic diarrhea in the murine ovalbumin (OVA)-induced allergic diarrhea model.. BALB/c mice were orally treated with PG102, dexamethasone or water for 9 days on a daily basis, followed by subcutaneous injection with OVA on day 0. Animals were orally administrated with OVA from day 7, 3 times a week, over a period of approximately 20 days. Incidence of diarrhea, serum, OVA-restimulated splenocytes and lamina propria lymphocytes were analyzed.. Oral administration of PG102 could suppress the incidence of diarrhea in a murine allergic diarrhea model. The amelioration of allergic diarrhea by PG102 was accompanied with the inhibition of mast cell infiltration into the large intestine. The serum level of IgE, IL-6 and MCP-1 was decreased in PG102-treated mice. When splenocytes were isolated from respective groups and cultured in the presence of OVA, cells from PG102-administrated animals produced lesser amounts of IL-6 and MCP-1.. PG102 has the potential to be used as a preventive for food allergic diseases.

Topics: Actinidia; Animals; Calcimycin; Cell Movement; Chemokine CCL2; Dexamethasone; Diarrhea; Disease Models, Animal; Female; Food Hypersensitivity; Immunoglobulin E; Interleukin-10; Interleukin-4; Interleukin-6; Intestine, Large; Lymphocytes; Mast Cells; Mice; Mice, Inbred BALB C; Mucous Membrane; Ovalbumin; Plant Extracts; Rats; Spleen

The pathophysiological mechanism of Campylobacter jejuni (enterotoxigenic) induced secretory diarrhoea remains least understood. To investigate the mechanism(s) involved, the unidirectional fluxes of Na+ and Cl- were measured across the C. jejuni live culture infected and control (non infected) rat ileum (unstriped), in vitro by Ussing technique under short circuit conditions, in the presence or absence of: Ca2+ ionophore A23187 (5 microM), 1-verapamil (100 microM), calmodulin (CaM) antagonist W-7 (100 microM), dantrolene (25 microM), protein kinase C (PKC) activator PMA (100 ng/ml) and H-7 (60 microM), selective inhibitor of PKC. There was net absorption of Na+ and enhanced Cl- secretion in infected animals while in control animals there was net absorption of Na+ and marginal secretion Cl-.Ca2+ ionophore A23187 mimicked the effects of C. jejuni infection whereas 1-verapamil had significant antisecretory effect on Na+ and Cl- secretion in infected animals. In vitro measurement of undirectional 45Ca fluxes in Ussing chamber experiments revealed net absorption of Ca2+ in infected rat ileum as compared to net secretion of Ca2+ in control rat ileum. These observations clearly indicate that there is increased stimulation of Ca2+ uptake from extracellular milieu to the enterocytes during C. jejuni-induced diarrhoea. The intracellular calcium levels (Ca2+]i (as measured by fluorescent probe Fura-2AM) were found to be raised significantly (P < 0.0001) in enterocytes isolated from C. jejuni infected ileum as compared to the enterocytes from control ileum. The observed increase in [Ca2+]i in enterocytes isolated from C. jejuni live culture supernatant treated rat ileum further shows the involvement of enterotoxin in diarrhoeal process. Dantrolene decreased significantly C. jejuni-induced net Na+ and Cl- secretion but it could not reverse it to absorption suggesting the partial involvement of Ca2+ mobilised from intracellular stores in mediating secretion. W-7 failed to inhibit the C. jejuni-induced net Na+ and Cl- secretion. In addition the CaM activity estimated in intestinal microvillar core remained same in both the control and C. jejuni infected animals. This indicates that C. jejuni-induced diarrhoea is not mediated through the activation of Ca(2+)-CaM complex pathway of the Ca2+ messenger system. The PKC activator PMA, induced net secretion of Na+ and Cl- in the control animals but it could not enhance further the C. jejuni-induced Na+ and Cl- secretion, sugg

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Calcimycin; Calcium; Calmodulin; Campylobacter Infections; Campylobacter jejuni; Chlorides; Cyclic AMP; Dantrolene; Diarrhea; Enzyme Activation; Ileum; In Vitro Techniques; Ion Transport; Isoquinolines; Male; Piperazines; Protein Kinase C; Rats; Rats, Wistar; Sodium; Tetradecanoylphorbol Acetate; Verapamil

The capacity of the small intestinal mucosa to generate leukotriene B4 (LTB4) and C4 (LTC4) in children with coeliac disease (CD) was investigated by measuring the production of LTB4 and LTC4 in intestinal biopsy specimens after stimulation with 10 microM calcium ionophore A23187. In addition, we examined the relationship between the production of LTB4 and LTC4 in the small intestinal mucosa and symptoms of diarrhoea. LTB4 and LTC4 production was significantly higher in biopsies from patients with active CD than from controls (p < 0.05 and p < 0.01, respectively). There was no significant difference in LTB4 and LTC4 production between patients with inactive CD and controls. In both patients with active CD and controls, no difference in LTB4 and LTC4 production was observed between the patients with and without diarrhoea. These findings suggest that enhanced generation of LTB4 and LTC4 in the small intestinal mucosa may contribute to the pathophysiology of CD but would not be related to the development of diarrhoea.

Topics: Calcimycin; Celiac Disease; Child; Child, Preschool; Data Interpretation, Statistical; Diarrhea; Humans; In Vitro Techniques; Infant; Intestinal Mucosa; Intestine, Small; Leukotriene B4; Leukotriene C4; Radioimmunoassay

The transmucosal fluxes of Na+ and Cl- were studied in Giardia lamblia infected mice in the presence or absence of phorbol-12-myristate-13-acetate (PMA), the activator of protein kinase C (PKC) or 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine (H-7), the inhibitor of PKC or Ca(2+)-calmodulin. There was net secretion of Na+ and Cl- in infected animals, while in control animals there was net absorption of these ions. The addition of ionophore or PMA resulted in net secretion of Na+ and Cl- in the control group while in the infected group there was no change in the fluxes of these ions. The selective potent inhibitor of protein kinase C, H-7, reversed the secretion of Na+ and Cl- in infected group to absorption. The addition of PMA and Ca(2+)-ionophore together in the infected group had a partial additive effect. This study suggests that G. lamblia induced fluid secretion involves protein kinase C and further protein kinase C acts in synergism with calcium.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Biological Transport; Calcimycin; Calcium; Chlorides; Diarrhea; Giardia lamblia; Intestinal Mucosa; Isoquinolines; Mice; Piperazines; Protein Kinase C; Sodium; Tetradecanoylphorbol Acetate

The unidirectional fluxes of Na+ and Cl- were studied in Salmonella typhimurium enterotoxin-treated rats. There was net secretion of Na+ and Cl- in toxin-treated animals, while in control animals there was net absorption of these ions. In the presence of the Ca(2+)-ionophore, there was net secretion of Na+ and Cl- in the control group, while the ionophore enhanced the secretion of these ions in experimental animals. The calcium channel blocker, verapamil, decreased the secretion induced by salmonella toxin, but could not reverse the secretion to absorption. There was no difference in the net absorption of Ca2+ in both the control and experimental animals. There was a significant increase in the intracellular free calcium concentrations in enterocytes isolated from toxin-treated rat intestines as compared to that in enterocytes isolated from control animals. In the presence of PMA (phorbol-12-myristated-13-acetate) there was net secretion of Na+ and Cl- in the control group, while in the experimental group there was no change in the fluxes of these ions. The selective, potent inhibitor of protein kinase C, H-7 (1-(5-isoquinolinylsulphonyl)-2-methylpiperazine) reversed the secretion of Na+ and Cl- in the toxin-treated group to absorption. The addition of indomethacin also inhibited the secretion induced by salmonella toxin, but failed to reverse it to absorption. However, the addition both H-7 and indomethacin to the experimental group had a partial additive effect. These studies demonstrate that the Salmonella enterotoxin-mediated fluid secretion involves protein kinase C and the arachidonic acid metabolites and perhaps does not involve the extracellular calcium pools.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Animals; Arachidonic Acid; Calcimycin; Calcium; Chlorides; Diarrhea; Enterotoxins; Indomethacin; Intestinal Mucosa; Intestine, Small; Isoquinolines; Male; Piperazines; Prostaglandins; Protein Kinase C; Rats; Rats, Inbred Strains; Salmonella typhimurium; Sodium; Tetradecanoylphorbol Acetate; Verapamil; Water-Electrolyte Balance

The unidirectional fluxes of Na+, Cl- and Ca2+ and activities of calmodulin in the intestinal microvillar core were studied in Escherichia coli heat-stable enterotoxin-treated mice. There was net secretion of Na+ and Cl- in toxin-treated animals, while in control animals there was net absorption of these ions. In both control and experimental animals, there was net absorption of Ca2+; however, the absorption was significantly higher (P less than 0.01) in experimental animals when compared to controls. In the presence of Ca2+-ionophore, there was a net secretion of Na+ and Cl- in controls, while the Ca2+-ionophore could not cause any change in the fluxes of these ions in experimental animals. The activity of calmodulin was significantly higher (P less than 0.01) in experimental animals. Verapamil, a calcium channel blocker, and trifluoperazine, a calmodulin inhibitor, reversed the effects of Ca2+-ionophore and heat-stable enterotoxin. These studies demonstrate that the toxin acts through Ca2+-calmodulin, and secretion of Na+ and Cl- in experimental animals is due to an increase in calcium absorption and an increase in calmodulin activity in the intestinal microvillar core.

Topics: Animals; Bacterial Toxins; Calcimycin; Calcium; Calmodulin; Chlorides; Diarrhea; Enterotoxins; Escherichia coli; Escherichia coli Proteins; Intestinal Absorption; Intestinal Mucosa; Mice; Sodium; Trifluoperazine; Verapamil

The mucosal-to-serosal fluxes of 3-O-methyl-D-glucose, a non-metabolizable analogue of D-glucose, were carried out in control and heat-stable enterotoxin treated mice in the presence or absence of Ca2+-ionophore, Ca2+-channel blocker, calmodulin inhibitor and Na+-K+-ATPase inhibitor. The transport of the sugar was significantly decreased (p less than 0.01) in the experimental animals. In the presence of Ca2+-ionophore, the uptake of the sugar decreased significantly (p less than 0.01) only in the control group while experimental group remained unaffected. Ca2+ channel blocker and calmodulin inhibitor significantly increased (p less than 0.01) the uptake of sugar in both the groups, however, the changes were more pronounced in the experimental group. Ouabain blocked the uptake of the sugar in both the groups. These studies indicated that heat-stable enterotoxin inhibit Na+-K+-ATPase by increasing Ca2+ uptake and calmodulin activity, thus resulting in decreased uptake of 3-O-methyl-D-glucose in heat-stable enterotoxin treated mice.

Topics: 3-O-Methylglucose; Animals; Bacterial Toxins; Calcimycin; Calcium; Calmodulin; Carbohydrate Metabolism; Diarrhea; Enterotoxins; Escherichia coli Proteins; Intestinal Mucosa; Methylglucosides; Mice; Trifluoperazine; Verapamil