Role of 5-HT in cholera toxin-induced mucin secretion in the rat small intestine

1996 ◽  
Vol 270 (6) ◽  
pp. G1001-G1009 ◽  
Author(s):  
B. A. Moore ◽  
K. A. Sharkey ◽  
M. Mantle
Keyword(s):  
Small Intestine ◽  
Receptor Antagonist ◽  
Cholera Toxin ◽  
Receptor Subtypes ◽  
Rat Small Intestine ◽  
Mucin Secretion ◽  
Common Pathway ◽  
Distal Small Intestine ◽  
Intestinal Segments

We examined the role of 5-hydroxytryptamine (5-HT) in cholera toxin (CT)-induced mucin secretion in the proximal and distal regions of the rat small intestine. Neither the 5-HT2 receptor antagonist ketanserin nor the cyclooxygenase inhibitor indomethacin was capable of inhibiting choleraic mucin secretion. However, in the presence of the mixed 5-HT3/4 receptor antagonist tropisetron at doses that block both receptor subtypes, the secretory response was reduced to baseline levels in the proximal and distal small intestine. The selective 5-HT3 receptor antagonist ondansetron had no significant effect. These findings suggest that choleraic mucin secretion is mediated primarily through the activation of a 5-HT4-like receptor. Mucin secretion in response to the exogenous application of 5-HT occurs via two pathways: one is mediated by a 5-HT4-like receptor and is capsaicin sensitive but tetrodotoxin (TTX) insensitive, and one lacks the capsaicin-sensitive 5-HT4-mediated response but is TTX sensitive. Both converge on a common pathway that is cholinergic. No significant differences were observed between proximal and distal intestinal segments.

Neural mediation of cholera toxin-induced mucin secretion in the rat small intestine

1993 ◽  
Vol 265 (6) ◽  
pp. G1050-G1056 ◽  
Author(s):  
B. A. Moore ◽  
K. A. Sharkey ◽  
M. Mantle
Keyword(s):  
Small Intestine ◽  
Cholera Toxin ◽  
Fold Increase ◽  
Open Loop ◽  
Sensory Nerves ◽  
Loop Model ◽  
Rat Small Intestine ◽  
Mucin Secretion ◽  
Distal Small Intestine

We examined the role of enteric nerves in cholera toxin (CT)-induced mucin secretion in proximal and distal regions of rat small intestine. Stimulation of intestinal loops with 120 micrograms (1.5 mumol) CT using an in vitro open-loop model resulted in an approximately four-fold increase in luminal mucin content over unstimulated controls in both regions of the gut. Prior treatment of loops with tetrodotoxin had no effect on the amount of mucin released in response to CT. However, permanent destruction of primary sensory afferent nerves by neonatal treatment of rats with capsaicin reduced the mucin response to CT to baseline levels in both regions. In normal animals, atropine resulted in approximately 40% inhibition of mucin secretion in both the proximal and distal small intestine. The atropine-sensitive secretory response appears to be a component of the capsaicin-sensitive response. These results suggest that choleraic mucin secretion is mediated primarily by a capsaicin-sensitive neurogenic pathway involving local activation of sensory nerves, which may then elicit mucin secretion through interaction with cholinergic nerves.

Sequence, tissue distribution, and functional characterization of the rat fructose transporter GLUT5

1993 ◽  
Vol 264 (6) ◽  
pp. G1169-G1176 ◽  
Author(s):  
E. B. Rand ◽  
A. M. Depaoli ◽  
N. O. Davidson ◽  
G. I. Bell ◽  
C. F. Burant
Keyword(s):  
Small Intestine ◽  
Functional Characterization ◽  
Cdna Probe ◽  
Amino Acid Identity ◽  
Human Testis ◽  
Cdna Clones ◽  
Rat Tissues ◽  
Rat Small Intestine ◽  
Cross Hybridization ◽  
Distal Small Intestine

cDNA clones encoding rat GLUT5-small intestinal facilitative hexose transporter were isolated from a jejunum library by cross-hybridization with a human GLUT5 cDNA probe. The cDNA sequence indicates that rat GLUT5 is composed of 502 amino acids and has 81.5% amino acid identity and 87.3% similarity with the sequence of human GLUT5. Expression of synthetic rat GLUT5 mRNA in Xenopus oocytes showed that rat GLUT5 was able to mediate the uptake of fructose and, to a lesser extent, of glucose. RNA blotting studies showed that GLUT5 mRNA was present in rat small intestine, kidney, and brain. Although GLUT5 mRNA is expressed in human testis, adipose tissue, and skeletal muscle, it could not be detected by RNA blotting in these rat tissues. Developmental studies showed low levels of GLUT5 mRNA in rat small intestine and kidney during the prenatal period with a rapid induction of GLUT5 expression occurring postnatally. In situ hybridization studies of GLUT5 mRNA expression in the small intestine revealed differential expression along the crypt-villus axis with the highest levels of mRNA being in the midvillus region. In addition, there was quantitatively more GLUT5 mRNA detected in the proximal as opposed to the distal small intestine.

scholarly journals Inhibitory role of the distal small intestine on the gastric secretory response to meals in man

1978 ◽  
Vol 74 (4) ◽  
pp. 704-707 ◽  
Author(s):  
Jonathan E. Clain ◽  
Vay Liang W. Go ◽  
Juan-R. Malagelada
Keyword(s):  
Small Intestine ◽  
Secretory Response ◽  
Distal Small Intestine ◽  
Inhibitory Role

Imaging the induction and spread of seizure activity in the isolated brain of the guinea pig: the roles of GABA and glutamate receptors

1996 ◽  
Vol 76 (5) ◽  
pp. 3471-3492 ◽  
Author(s):  
P. Federico ◽  
B. A. MacVicar
Keyword(s):  
Guinea Pig ◽  
Receptor Antagonist ◽  
Glutamate Receptor ◽  
Entorhinal Cortex ◽  
Seizure Activity ◽  
Olfactory Cortex ◽  
Receptor Subtypes ◽  
Amygdaloid Nucleus ◽  
Field Potentials

1. The induction and spread of seizure activity was studied using imaging and electrophysiological techniques in the isolated whole brain of the guinea pig. We examined the role of GABA and glutamate receptor subtypes in controlling the spread of seizure activity across the olfactory cortex from a focus in the entorhinal cortex. Seizure spread was monitored by video imaging of intrinsic optical signals (reflectance changes) combined with multiple extracellular recordings. Both the unilateral and bilateral spread of seizure activity was monitored in different experiments. 2. Electrical stimulation of the lateral entorhinal cortex (10-15 V, 5 Hz, 5-10 s) evoked seizure activity that originated in the entorhinal cortex/hippocampus and later spread preferentially toward the posteromedial cortical amygdaloid nucleus ipsilaterally and bilaterally. The pattern of seizure spread in a given brain was highly reproducible. 3. The influence of gamma-aminobutyric acid (GABA) receptors on the spread of seizure activity was monitored at higher resolution on one side of the brain. Perfusion of a low concentration of the GABAA antagonist bicuculline methiodide (20 microM) resulted in spontaneous seizures that spread to the posteromedial cortical amygdaloid nucleus more rapidly than electrically evoked seizures [spread times: 5.5 +/- 3.7 s vs. 15.5 +/- 2.7 s, respectively (means +/- SE)]. Seizure spread was also more extensive in the presence of bicuculline involving the posterior perirhinal cortex and larger areas over the medial amygdala. Higher concentrations of bicuculline (100 microM) resulted in even more widespread propagation of spontaneous seizure activity throughout the olfactory cortex as well as to the perirhinal, insular, and occipital cortices. This concentration of bicuculline also further reduced the time required for seizure activity to spread from the entorhinal cortex to the posteromedial cortical amygdaloid nucleus (spread time = 2.3 +/- 1.7 s). The GABAB antagonist, CGP 35348 (200 microM), in contrast, had no significant effect of seizure induction or propagation. 4. The role of glutamate receptor subtypes in seizure propagation was studied by examining the bilateral spread of seizures. Perfusion of the kainate/alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (K/A) receptor antagonist (6-cyano-7-nitroquinoxaline-2,3-dione, CNQX, 20 microM) completely and reversibly suppressed stimulus-evoked seizure activity as detected electrophysiologically and optically. CNQX also reduced the magnitudes of field potentials recorded in the isolated brain in a reversible manner by an average of 70.8 +/- 2.21% of control. The N-methyl-D-aspartate (NMDA) receptor antagonist dibenzocyclohepteneimine (MK-801) did not significantly alter the magnitudes or shapes of field potentials recorded in the isolated brain nor did it significantly alter seizure activity measured optically or electrophysiologically. 5. Perfusion of the metabotropic glutamate receptor agonist [trans-1-amino-(IS,3R)-cyclopentanedicarboxylic acid (trans-ACPD), 150 microM] completely and reversibly suppressed stimulus-evoked seizure activity as detected electrophysiologically and optically. The magnitudes of field potentials recorded in the isolated brain also were reduced by trans-ACPD an average of 75.4 +/- 5.39% of control values. 6. These results demonstrate that GABAA-mediated transmission is functionally present and may play an important role in epileptic tissue in limiting the spread of seizure activity from the entorhinal cortex to the posteromedial cortical amygdaloid nucleus and in creating functional pathways or preferential routes of seizure spread. GABAB-mediated postsynaptic inhibition played no significant role in the induction or spread of seizure activity in this study. K/A receptors but not NMDA receptors are necessary for the induction and subsequent spread of seizure activity originating in the entorhinal cortex/hippocampus.

Mechanisms of endothelin-1 induced mucosal dysfunction in the rat small intestine: Role of leukocytes

1998 ◽  
Vol 114 ◽  
pp. A384
Author(s):  
B. Karakoyun ◽  
T. Coskun ◽  
A. Bozkurt ◽  
B.Ç. Yegen ◽  
M. Yüksel ◽  
...  
Keyword(s):  
Small Intestine ◽  
Rat Small Intestine ◽  
Endothelin 1

scholarly journals Role of estrogen receptor subtypes in estrogen-induced organ-specific vasorelaxation after trauma-hemorrhage

2008 ◽  
Vol 295 (5) ◽  
pp. H2061-H2067 ◽  
Author(s):  
Zheng F. Ba ◽  
Irshad H. Chaudry
Keyword(s):  
Estrogen Receptor ◽  
Small Intestine ◽  
Receptor Subtypes ◽  
Circulating Blood Volume ◽  
Heart Performance ◽  
Organ Specific ◽  
Isolated Perfusion ◽  
Specific Organ ◽  
T Values

Although endothelin-1 (ET-1)-induced organ hypoperfusion after trauma-hemorrhage is improved by estrogen administration, it remains unclear whether estrogen receptor (ER) subtypes play any role in the attenuation of ET-1-induced vasoconstriction in any specific organ bed. To investigate this, isolated perfusion experiments in the heart, liver, small intestine, kidney, and lung were carried out in sham, at the time of maximum bleedout (MBO; i.e., 5-cm midline incision, with removal of 60% of circulating blood volume over 45 min to maintain a mean blood pressure of 40 mmHg), and 2 h after trauma-hemorrhage and resuscitation (T-H/R). Organ-specific ET-1-induced vasoconstriction was evaluated, and the effects of 17β-estradiol (E2) and ER-specific agonists propylpyrazole triol (PPT; ERα agonist) and diarylpropionitrile (DPN; ERβ agonist) were determined. ET-1 induced the greatest vasoconstriction in sham animals, with the strongest response in the kidneys, followed by the small intestine and liver. ET-1-induced responses were weakest in the heart and lungs. ET-1-induced vasoconstriction was evident at the time of MBO but was significantly decreased at 2 h after T-H/R. ERβ plays an important role in cardiac performance, as evidenced by improved heart performance (+dP/d t) in the presence of DPN. DPN also induced a greater effect than PPT in the reduction of ET-1-induced vasoconstriction in the kidneys and lungs. In contrast, PPT attenuated ET-1-induced vasoconstriction in the liver, whereas both DPN and PPT were equally effective in the small intestine. The increased +dP/d t values induced by E2, DPN, or PPT were evident at the time of MBO but were significantly decreased at 2 h after T-H/R. These data indicate that the effects of ET-1 on vasoconstriction and the role of ER subtypes in estrogen-induced vasorelaxation are organ specific and temporally specific after trauma-hemorrhage.

Evidence of stereoselective and segmental-dependant transport of chiral antidiabetic drug nateglinide along the rat small intestine: possible role of efflux transporters

2012 ◽  
Vol 22 (5) ◽  
pp. 2403-2410 ◽  
Author(s):  
Srinivas Maddi ◽  
Shravan Kumar Yamsani ◽  
Adukondalu Devandla ◽  
Gerhard Scriba ◽  
Madhusudan Rao Yamsani
Keyword(s):  
Small Intestine ◽  
Efflux Transporters ◽  
Rat Small Intestine ◽  
Antidiabetic Drug

Pathology of Infectious Diarrhea of Infant Rats (IDIR) Induced by an Antigenically Distinct Rotavirus

1989 ◽  
Vol 26 (5) ◽  
pp. 376-385 ◽  
Author(s):  
A. C. Huber ◽  
R. H. Yolken ◽  
L. C. Mader ◽  
J. D. Strandberg ◽  
S. L. Vonderfecht
Keyword(s):  
Small Intestine ◽  
Post Inoculation ◽  
Diagnostic Features ◽  
Distal Small Intestine ◽  
Precursor Material ◽  
Viral Particles ◽  
Intestinal Segments ◽  
Villous Height ◽  
Small Intestinal ◽  
Group B

Suckling rats were inoculated with a group B rotavirus to determine the progression of the morphologic changes induced in the intestine by this virus. Several changes were observed by light microscopy 1 day after viral inoculation: shortening of small intestinal villi, villous epithelial necrosis, and villous epithelial syncytia. The lesions were most often present in the distal small intestine, although other small intestinal segments were affected to a lesser degree. By day 3 post-inoculation, epithelial necrosis, and syncytia were no longer present; however, the villous epithelium was disorganized and irregularly vacuolated, and intestinal crypt epithelium was hyperplastic. Alterations in villous height to crypt depth ratios were present in portions of the small intestine for the remainder of the 12-day study period. Epithelial syncytia appeared to form by the breakdown of the lateral interdigitating membranes of the absorptive villous epithelium. Viral particles, abundant in the syncytia, appeared to form from amorphous or reticular arrays of viral precursor material. Group B rotaviral antigens, as detected by indirect immunofluorescence, were present in large amounts in the small intestinal villous epithelium only on the first day after viral inoculation. These studies show that two important diagnostic features of group B rotaviral infections of rats, epithelial syncytia and viral antigen as determined by immunofluorescence, are present only on the first day of disease. These findings should be taken into consideration when attempting to diagnose disease induced by this agent.

Sign in / Sign up

Export Citation Format

Share Document