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M D Murillo

Publications and source records attributed to M D Murillo.

24 records · Page 2Linked to original sources
PubMed1990

Effect of VIP on sugar transport in rabbit small intestine in vitro.

The vasoactive intestinal peptide (VIP) has shown to be widely distributed in the gastrointestinal mucosa, submucosa and nerves, and the existence of VIP receptors on the basolateral membrane of enterocytes has been recently reported for many species. The interaction of VIP with its receptors seemed to increase cyclic AMP level, and this nucleotide has been shown to be responsible for the intestinal secretion produced by VIP. The present study confirms that VIP inhibits the intestinal absorption of D-galactose. This effect seems to be due to the inhibition of the Na(+)-independent basolateral intestinal sugar transport system. RMI 12330A, described as adenylate cyclase inhibitors, blocked the VIP action. These findings suggest that cyclic AMP might be responsible for the inhibition of Na(+)-independent transport of D-galactose across the basolateral membrane. Moreover, results obtained to determine the possible role of calcium in the action of VIP suggest that Ca2+ play a part, directly or indirectly, in the inhibition of the D-galactose transport across the basolateral membrane produced by VIP.

Animals↗
PubMed1990

Development and evaluation of a simplified dot-blot method for detecting the delta F508 mutation in cystic fibrosis.

The recent discovery of the cystic fibrosis gene enables DNA-based testing for the direct identification of the deletion of three basepairs coding for phenyalanine at codon 508, the major mutation responsible for the disease. This mutation can be detected by analysis of amplified DNA with allele-specific oligonucleotide probes. We have simplified the procedure of Kerem et al. (Science 1989;245:1073-80) so that the assay can be routinely completed in one working day, starting with an extracted DNA sample. Addition of salmon-sperm DNA to the product of the polymerase chain reaction greatly improved the quality of the hybridization signal. The precision of the method was evaluated by blind analysis and interpretation of results for 100 specimens from 25 patients. The same result was obtained for each patient analyzed separately four times, and four independent observers agreed on the interpretation of results for all 100 specimens. No specimen required repeat analysis to produce interpretable results. We conclude that this method is reliable and convenient for routine clinical laboratory use.

Cystic Fibrosis↗
PubMed1989

Effect of serotonin on D-galactose transport across the rabbit jejunum.

The patterns of storage and release of serotonin found in the enterochromaffin cells of the intestinal mucosa suggest that this hormone may be an important modulator of intestinal functions. Serotonin has been shown to produce secretion of water and electrolytes in rabbit ileum, but the hormone does not appear to interact significantly with other transport processes. The aim of the present study was to determine the effect of serotonin on D-galactose absorption in rabbit jejunum. The results obtained show that serotonin (10(-8) and 10(-6)M) partially reduced (by 20 and 40% respectively) D-galactose uptake across the mucosal border. This effect was concentration-dependent, and it seemed to be caused by the inhibition of Na+-dependent sugar transport. Methysergide, an antagonist of serotonin which binds with receptor 2 of serotonin, blocked the effect of serotonin. These findings suggest that serotonin may act as a regulator of sugar intestinal absorption, and that this serotonin regulation could be mediated by a direct or indirect action of the complex serotonin-receptor, which may inhibit the Na+-dependent transport system of sugars located in the brush-border membrane.

Animals↗
PubMed1988

Influence of VIP on D-galactose transport across rabbit jejunum in vivo.

D-galactose absorption during 1 min perfusion periods was not affected by the presence of 10(-7)-10(-8) M VIP in the sugar solution, but exposure of mucosa to VIP for 5 min inhibited sugar absorption in the subsequent periods of perfusion. This inhibition is reversed after washing with saline solution. The effect of VIP disappeared when 10(-6) M RMI 12330A was added to the incubation solution together with 10(-7) M VIP and 1 mM D-galactose solution. These results suggest the existence of VIP receptors on the brush border membrane. The action of VIP could be mediated through the cAMP system.

Animals↗