Peptide YY enhances NaCl and water absorption in the rat colon in vivo

Peptide YY (PYY) is thought to possess paracrine and endocrine functions. The highest concentrations of this peptide are in the colonic mucosa. The effect of PYY on electrolyte and water transport in the rat colon was studied in vivo. Under urethane anesthesia, rat colonic loops were perfused at a constant rate with physiological buffer solution containing phenol red as a nonabsorbable volume marker, and net movements of water, sodium, chloride and potassium in the perfused colon were determined every 10 min. Intravenous administration of PYY produced a dose-dependent increase in the net absorption of sodium chloride and water, as well as a decrease in the net secretion of potassium. PYY inhibited the reduction in net absorption of sodium chloride and water evoked by vasoactive intestinal peptide (VIP), but did not affect the VIP-evoked increase in net potassium secretion.These findings suggest that PYY acts as an enhancer of sodium chloride and water absorption and as an antagonist to VIP-induced secretion in the colon.     

Peptide YY enhances NaCl and water absorption in the rat colon in vivo.

Peptide YY (PYY) is thought to possess paracrine and endocrine functions. The highest concentrations of this peptide are in the colonic mucosa. The effect of PYY on electrolyte and water transport in the rat colon was studied in vivo. Under urethane anesthesia, rat colonic loops were perfused at a constant rate with physiological buffer solution containing phenol red as a nonabsorbable volume marker, and net movements of water, sodium, chloride and potassium in the perfused colon were determined every 10 min. Intravenous administration of PYY produced a dose-dependent increase in the net absorption of sodium chloride and water, as well as a decrease in the net secretion of potassium. PYY inhibited the reduction in net absorption of sodium chloride and water evoked by vasoactive intestinal peptide (VIP), but did not affect the VIP-evoked increase in net potassium secretion. These findings suggest that PYY acts as an enhancer of sodium chloride and water absorption and as an antagonist to VIP-induced secretion in the colon.     

Interaction of basic dyes with the thiamine transport system inSaccharomyces cerevisiae

Summary Basic dyes such as methylene blue and triphenyltetrazolium chloride were found to inhibit thiamine transport inSaccharomyces cerevisiae. Conversely, the reduction of methylene blue and triphenyltetrazolium chloride by yeast cells was inhibited by thiamine. A thiamine transport mutant ofSaccharomyces cerevisiae showed decreased utilization of these dyes. From the results, the possibility that the uptake of basic dyes may proceed via a membrane-bound thiamine-binding protein in the thiamine transport system of the yeast is discussed.This work was supported in part by a grant from the Ministry of Education, Science and Culture of Japan.     

Effect of cadmium chloride on steroidogenic enzymes in the Bidder's organ of the toad (Bufo melanostictus)

Injection of cadmium chloride in a toad increases both the delta 5-3 beta-hydroxy-steroid dehydrogenase and 17 beta-hydroxysteroid dehydrogenase activities in Bidder's organ.     

Anatomical relationships of the ionocytes (chloride cells) with the branchial venous compartment: definition of two types of epithelium in fish gills]

The fish gill, a gas exchanger and osmoregulatory structure, is separated from the external milieu by two well defined types of epithelium. One, the primary lamellar epithelium, faces the venous compartment of the primary lamellae. It contains chloride cells whose extracellular spaces drain into the venous system. The other, the secondary lamellar epithelium, faces the arterio-arterial capillaries of the secondary lamellae and is made-up of an other cell type. This arrangement is seen in all classes of fishes, except Dipnoans, its functional significance is that the activity of the chloride cells directly affects the venous compartment.     

Protection against mercuric chloride nephropathy by sodium selenite in the rat]

Daily intraperitoneal injection of 2.5 or 5 mumole HgCl2 to male Rats weighing 250 to 350 g induces an early intense increase of urine gamma-glutamyl transferase activity. In the same conditions, equimolecular administration of sodium selenite and mercuric chloride induces no increase of the enzymuria for the low dose: for the high dose- a minor and more persistent increase of urine GGT is observed. Thus, the activity of urines GGT allows, in vivo, to establish that sodium selenite protects Rat kidney against toxic effects of mercuric chloride.     

Aging of the erythrocyte. XV. Isoosmotic lysis times

Summary Isoosmotic lysis times of various density (age) fractions of human, pig and ox erythrocytes in glycerol and ammonium chloride solutions decreased with increasing cell density.I am indebted to Prof. W. Leyko for many stimulating discussions.     

Depressant effects of major tranquillizers on contact hypersensitivity to picryl chloride in the mouse

Summary Chlorpromazine, levomepromazine, thioproperazine, promethazine and haloperidol were found to significantly depress contact hypersensitivity to picryl chloride in the mouse, a model of cell-mediated immune response.The skilled technical assistance of R. Tedone is warmly acknowledged.     

Effects of salicylate on the electrical properties of the proximal convoluted tubule of Necturus maculosus]

The effects of peritubular salicylate for chloride substitution were studied in the isolated perfused Necturus kidney. This substitution resulted in changes of cell membrane p.d., varying from tubule to tubule; the withdrawal of the test-anion invariably produced a steep and prolonged depolarization. Exposure of the tissue to salicylate brought about, in addition, electrical uncoupling of junctional membranes, which was not related to concomitant changes of membrane p.d.     

Effects of lithium chloride on peripheral acetylcholine release and brain acetylcholine levels in the guinea-pig.

Lithium chloride administered acutely or chronically to guinea-pigs had no effect on brain level of acetylcholine or on peripheral release of acetylcholine from longitudinal muscle of the ileum. The results suggest differences between in vitro and in vivo action of lithium.     

From the endoplasmic reticulum to the plasma membrane: mechanisms of CFTR folding and trafficking

CFTR biogenesis starts with its co-translational insertion into the membrane of endoplasmic reticulum and folding of the cytosolic domains, towards the acquisition of a fully folded compact native structure. Efficiency of this process is assessed by the ER quality control system that allows the exit of folded proteins but targets unfolded/misfolded CFTR to degradation. If allowed to leave the ER, CFTR is modified at the Golgi and reaches the post-Golgi compartments to be delivered to the plasma membrane where it functions as a cAMP- and phosphorylation-regulated chloride/bicarbonate channel. CFTR residence at the membrane is a balance of membrane delivery, endocytosis, and recycling. Several adaptors, motor, and scaffold proteins contribute to the regulation of CFTR stability and are involved in continuously assessing its structure through peripheral quality control systems. Regulation of CFTR biogenesis and traffic (and its dysregulation by mutations, such as the most common F508del) determine its overall activity and thus contribute to the fine modulation of chloride secretion and hydration of epithelial surfaces. This review covers old and recent knowledge on CFTR folding and trafficking from its synthesis to the regulation of its stability at the plasma membrane and highlights how several of these steps can be modulated to promote the rescue of mutant CFTR.     

New paradigms of CFTR chloride channel regulation

The Cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel controls salt and water transport across epithelial tissues. Alterations in the activity of this ion channel lead to two major human diseases: cystic fibrosis (low CFTR activity) and secretory diarrhea (excessive CFTR activity). The goal of this article is to review recent developments in our understanding of two aspects of CFTR biology: (i) interactions between CFTR domains (intramolecular interactions) that control the gating of this epithelial chloride channel and (ii) interactions between CFTR and other proteins (intermolecular interactions) that couple the activity of this ion channel to additional cellular processes in epithelial cells (e.g. membrane traffic). Clarifying the nature of these interactions may lead to the development of novel strategies for treating diseases that involve the CFTR chloride channel. Received 12 October 1999; accepted 31 December 1999     

Evidence for reopening of the cranial neural tube in mouse embryos treated with cadmium chloride

Use of the whole-embryo culture technique resulted in experimental evidence that the pathogenesis of exencephaly in mouse embryos after cadmium chloride treatment results from reopening of the cranial neural tube.     

Evidence for reopening of the cranial neural tube in mouse embryos treated with cadmium chloride

Summary Use of the whole-embryo culture technique resulted in experiemtal evidence that the pathogenesis of exencephaly in mouse embryos after cadmium chloride treatment results from reopening of the cranial neural tube.     

Effects of lithium chloride on peripheral acetylcholine release and brain acetylcholine levels in the guinea-pig

Summary Lithium chloride administered acutely or chronically to guinea-pigs had no effect on brain level of acetylcholine or on peripheral release of acetylcholine from longitudinal muscle of the ileum. The results suggest differences between in vitro and in vivo action of lithium.To whom correspondence should be addressed.     

合成对乙酰氨基苯磺酰氯的新工艺

为了减少氯磺酸的用量,提高对乙酰氨基苯磺酰氯(P ASC)的收率,提出一种新的 P ASC合成工艺,即溶剂法 ClSO3H/PCl5联合氯磺化生产工艺.以乙酰苯胺为原料,通过氯磺酸磺化、五氯化磷氯化,合成 P ASC.在氯磺化过程中引入溶剂,并在反应后期加入助剂,用正交实验确定了最佳的反应条件及原料配比:n(乙酰苯胺)∶n(氯磺酸)∶n(五氯化磷)∶n(助剂)=1.0∶2.0~2.3∶1.0~1.3∶0.1.实验结果表明:新工艺降低了氯磺酸的用量58%,且相同成本条件下的收率比传统工艺提高10~12%     

Isethionate may not be an inert substitute for extracellular chloride in the central nervous system

Summary Replacement of extracellular chloride with isethionate or methylsulphate causes an increased efflux of 1-[¹⁴C]-GABA from the in vivo superfused rat cuneate nucleus. This raises the question of the suitability of these anions as inert substitutes for chloride in studies on the ionic dependency of membrane phenomena in the central nervous system.Supported in part by a grant from the Medical Endowment Funds of the University of Aberdeen.N. B. supported by grants from CAPES and FAPESP, Brazil, J. A. A. supported by grants from CNPq and FAPESP, Brazil.     

Effect of ascorbic acid on biotransformation and modification of the toxicity of mercurials in goldfish (Carassius auratus)

Summary Ascorbic acid mediated a small but significant degradation of methylmercury to inorganic mercury in goldfish (Carassius auratus) and reduced the toxicity of mercuric chloride despite its substantial conversion into organic form. This investigation was supported by a grant from the Fishing Industry Research Account of the Australian Department of Primary Industry.     

Deoxyribonuclease immobilized on the erythrocytes

Summary Bovine pancreatic deoxyribonuclease (DNase I) was immobilized on human erythrocytes with several procedures. DNase immobilized on the erythrocytes by chromic chloride showed DNase activity in vitro. Other binding procedures inhibit the immobilized DNase activity.     

Stimulation of calcitonin secretion in the fasting newborn rat by ingestion of triglycerides]

The stomach gavage of fat (triglycerides) in the fasting newborn Rat induced a marked increase in the plasma concentration of immunoreactive calcitonin after 30 and 60 mn. Calcium chloride given by the same route at the dose of 20 mg calcium per kg body weight had a poor effect on calcitonin secretion. This stimulation was probably mediated through some gastro-intestinal hormone that has to be uncovered.