Neuropeptide tyrosine (NPY) inhibits PGE2-induced fluid and electrolyte secretion in the rat jejunum in vivo

1985 ◽  
Vol 10 ◽  
pp. 236
Author(s):  
E. Beubler ◽  
A. Saria
2003 ◽  
Vol 15 (4) ◽  
pp. 417-425 ◽  
Author(s):  
G. Bogeski ◽  
N. P. Lean ◽  
P. D. Kitchener ◽  
A. Timar-Peregrin ◽  
G. J. Sanger ◽  
...  
Keyword(s):  

1989 ◽  
Vol 256 (2) ◽  
pp. G436-G441 ◽  
Author(s):  
C. Bianchi ◽  
G. Thibault ◽  
A. De Lean ◽  
J. Genest ◽  
M. Cantin

We have studied the localization and the characterization of atrial natriuretic factor (ANF) binding sites by radioautographic techniques. Quantitative in vitro radioautography with a computerized microdensitometer demonstrated the presence of high-affinity, low-capacity 125I-ANF-(99-126) binding sites (Kd, 48 pM; Bmax, 63 fmol/mg protein) mainly in the villi of 20-microns slide-mounted transverse sections of the rat jejunum. Competition curves showed 50% inhibitory concentrations of 55 and 1,560 pM for ANF-(99-126) and ANF-(103-123), respectively. In vivo electron microscope radioautography showed that 80% of the silver grains were localized on the lamina propria fibroblast-like cells, 18% on mature enterocytes, and 2% on capillaries. Bradykinin and adrenocorticotropin did not compete with ANF binding. These results demonstrate that ANF binding sites in the rat jejunum possess the pharmacological characteristics of functional ANF receptors encountered in other rat tissues, and ultrastructural radioautographs show their cellular distribution. Taken together, these results demonstrate the presence and the localization of specific binding sites for ANF in the jejunal villi of the rat small intestine.


1976 ◽  
Vol 14 (4) ◽  
pp. 1004-1010 ◽  
Author(s):  
F A Klipstein ◽  
C S Lee ◽  
R F Engert
Keyword(s):  

1986 ◽  
Vol 250 (6) ◽  
pp. G727-G735 ◽  
Author(s):  
H. Westergaard ◽  
K. H. Holtermuller ◽  
J. M. Dietschy

Assessment of intestinal absorptive function requires techniques for correcting transport constants for diffusion barrier resistance. These studies were done to develop such techniques for use in vivo. In one method the functional thickness of the unstirred water layer (d) in rat jejunum was quantitated electrically, and its minimal surface area (Sw) was measured directly. From these values the diffusion barrier resistance (d/Sw) decreased from 0.041 to 0.022 as the perfusion rate of the intestine was increased from 1.5 to 15 ml/min. In the second method apparent passive permeability coefficients (*P) were measured for a series of saturated fatty acids, and these increased with chain length. However, at the longest chain lengths tested, *P became proportional to their free diffusion coefficients, indicating that uptake was limited by the rate of diffusion up to the microvillus surface. From the rates of uptake of such diffusion-limited probes, the diffusion barrier resistance was again calculated and found to decrease from 0.041 to 0.022 as the rate of perfusion was increased from 1.5 to 15 ml/min. Over this same range of perfusion rates, the apparent Michaelis constant (*Km) for D-glucose transport decreased from 18.2 to 10.0 mM. Using either set of resistance terms and these apparent Km values, the true Km value for glucose transport in vivo was found to equal 0.8 mM when the barrier resistance was extrapolated to zero. Thus these data indicate that diffusion-limited probes can be utilized to measure unstirred layer resistance in the intestine of a live animal so that absolute transport parameters can be determined in vivo in experimental animals and, presumably, in humans.


1981 ◽  
Vol 91 (2) ◽  
pp. 205-211 ◽  
Author(s):  
P. G. DOREY ◽  
K. A. MUNDAY ◽  
B. J. PARSONS ◽  
JUDITH A. POAT ◽  
MARY E. UPSHER

A study has been made of the effects of chemical sympathectomy and ganglion blockade on the responses of rat jejunum in vivo to intravenous doses of angiotensin and noradrenaline capable of stimulating fluid transport. Pretreatment with 6-hydroxydopamine (chemical sympathectomy) or pentolinium tartrate (ganglion blockade) abolished the stimulatory actions of angiotensin II but left the responses to noradrenaline unimpaired. Dopamine, like noradrenaline, stimulated fluid transport but this response required very high dopamine infusion rates, was refractory to the dopamine antagonist sulpiride and was inhibited by the α-blocker phentolamine. The possible interaction between angiotensin and the intestinal sympathetics is discussed with reference to control of extracellular fluid volume.


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