Cholinergic agonist-induced pepsinogen secretion from murine gastric chief cells is mediated by M1 and M3 muscarinic receptors

2005 ◽  
Vol 289 (3) ◽  
pp. G521-G529 ◽  
Author(s):  
Guofeng Xie ◽  
Cinthia Drachenberg ◽  
Masahisa Yamada ◽  
Jürgen Wess ◽  
Jean-Pierre Raufman

Muscarinic cholinergic mechanisms play a key role in stimulating gastric pepsinogen secretion. Studies using antagonists suggested that the M3 receptor subtype (M3R) plays a prominent role in mediating pepsinogen secretion, but in situ hybridization indicated expression of M1 receptor (M1R) in rat chief cells. We used mice that were deficient in either the M1 (M1R−/−) or M3 (M3R−/−) receptor or that lacked both receptors (M1/3R−/−) to determine the role of M1R and M3R in mediating cholinergic agonist-induced pepsinogen secretion. Pepsinogen secretion from murine gastric glands was determined by adapting methods used for rabbit and rat stomach. In wild-type (WT) mice, maximal concentrations of carbachol and CCK caused a 3.0- and 2.5-fold increase in pepsinogen secretion, respectively. Maximal carbachol-induced secretion from M1R−/− mouse gastric glands was decreased by 25%. In contrast, there was only a slight decrease in carbachol potency and no change in efficacy when comparing M3R−/− with WT glands. To explore the possibility that both M1R and M3R are involved in carbachol-mediated pepsinogen secretion, we examined secretion from glands prepared from M1/3R−/− double-knockout mice. Strikingly, carbachol-induced pepsinogen secretion was nearly abolished in glands from M1/3R−/− mice, whereas CCK-induced secretion was not altered. In situ hybridization for murine M1R and M3R mRNA in gastric mucosa from WT mice revealed abundant signals for both receptor subtypes in the cytoplasm of chief cells. These data clearly indicate that, in gastric chief cells, a mixture of M1 and M3 receptors mediates cholinergic stimulation of pepsinogen secretion and that no other muscarinic receptor subtypes are involved in this activity. The development of a murine secretory model facilitates use of transgenic mice to investigate the regulation of pepsinogen secretion.

1993 ◽  
Vol 264 (4) ◽  
pp. G718-G727 ◽  
Author(s):  
J. M. Qian ◽  
W. H. Rowley ◽  
R. T. Jensen

Both gastrin and cholecystokinin (CCK) can stimulate pepsinogen release from chief cells, but controversy exists about the receptors or intracellular mediators involved. In the present study, we prepared isolated chief cells from guinea pig stomach (> 90% pure) to investigate the ability of gastrin and CCK to alter cell function. The COOH-terminal octapeptide of CCK (CCK-8) caused an eightfold increase in pepsinogen release (EC50, 54 nM). Both CCK-8 and gastrin increased inositol phosphates, with CCK-8 (1 microM) and gastrin (3 microM) causing a 40- and 14-fold increase in [3H]IP1, 10- and 6-fold for [3H]IP2, and 8- and 4-fold for [3H]IP3. CCK-8 caused a half-maximal increase in [3H]IP3 at 2 nM, and the dose-response curve was monophasic, whereas with gastrin the curve was biphasic, with an EC50 of the initial component (20% maximal) at 38 nM and the second component at 10 microM. L-364,718 (0.1 microM) inhibited the secondary increase seen with gastrin concentrations > 10 nM. The CCK-A-selective agonist A-71378 was 85-90% as efficacious as CCK-8 and was equally potent. With 0.1 microM L-364,718, A-71378 caused no increase in [3H]inositol phosphates until > 10 nM, whereas CCK-8 caused 15% of maximal increase at concentrations > 0.3 nM. Similar results were obtained with cytosolic calcium measured using fura-2 or on CCK-8- or gastrin-stimulated pepsinogen release. These results demonstrate that gastrin and CCK-8 can alter chief cell function by interacting with either a CCK-A or CCK-B/gastrin receptor. Both receptors are coupled to phospholipase C and cause changes in inositol phosphates, cytosolic calcium, and pepsinogen release; however, the intracellular amplification differs between the two receptor subtypes. Activation by CCK-related peptides of the CCK-A receptor subtype accounts for 85-90% of the maximal changes in cellular function, and activation of the CCK-B/gastrin receptor accounts for 10-20% of maximal changes.


1989 ◽  
Vol 169 (5) ◽  
pp. 1565-1581 ◽  
Author(s):  
C L Cooper ◽  
C Mueller ◽  
T A Sinchaisri ◽  
C Pirmez ◽  
J Chan ◽  
...  

Analysis of tissue lesions of the major reactional states of leprosy was undertaken to study the immune mechanisms underlying regulation of cell-mediated immunity and delayed-type hypersensitivity (DTH) in man. In situ hybridization hybridization of reversal reaction biopsy specimens for INF-gamma mRNA expression revealed a 10-fold increase in specific mRNA-containing cells over that observed in unresponsive lepromatous patients. Expression of huHF serine esterase, a marker for T cytotoxic cells, were fourfold increased in reversal reaction and tuberculoid lesions above that detected in unresponsive lepromatous individuals. Immunohistology of reversal reactions confirmed a selective increase of Th and T cytotoxic cells in the cellular immune response. Of interest, the microanatomic location of these serine esterase mRNA-containing cells was identical to the distribution of CD4+ cells. Analysis of erythema nodosum leprosum (ENL) lesions revealed differences in the underlying immune processes in comparison with reversal reaction lesions. Although phenotypic Th cells predominated in ENL lesions, IFN-gamma and serine esterase gene expression were markedly reduced. We suggest that reversal reactions represent a hyperimmune DTH response characterized by a selective increase of CD4+ IFN-gamma producing cells and T cytotoxic cells, which result in the clearing of bacilli and concomitant tissue damage. In contrast, ENL reactions may be viewed as a transient diminution of Ts cells and activity leading to a partial and transient augmentation in cell-mediated immunity, perhaps sufficient to result in antibody and immune complex formation, but insufficient to clear bacilli from lesions.


2000 ◽  
Vol 165 (1) ◽  
pp. 90-100 ◽  
Author(s):  
Margaret M. Durkin ◽  
Mary W. Walker ◽  
Kelli E. Smith ◽  
Eric L. Gustafson ◽  
Christophe Gerald ◽  
...  

1995 ◽  
Vol 268 (2) ◽  
pp. F220-F226 ◽  
Author(s):  
D. P. Healy ◽  
M. Q. Ye ◽  
M. Troyanovskaya

The physiological effects of angiotensin II (ANG II) on the kidney are mediated primarily by the ANG II type 1 (AT1) receptor. Two highly similar AT1 receptor subtypes have been identified in the rat by molecular cloning techniques, namely AT1A and AT1B. The intrarenal localization of the AT1A and AT1B receptor subtypes has not been studied by hybridization methods with subtype-specific receptor probes. Using radiolabeled probes from the 3' noncoding region of the AT1A and AT1B cDNAs, we localized AT1 mRNA in rat kidney by in situ hybridization. Specificity of the 3' noncoding region probes was tested by Northern blot and solution hybridization methods. AT1A mRNA levels were highest in the liver, kidney, and adrenal. In contrast, AT1B mRNA levels were highest in the adrenal and pituitary and low in kidney. Autoradiographic localization of 125I-[Sar1,Ile8]ANG II binding indicated that the highest levels of AT1 receptors were found in glomeruli and vascular elements. In situ hybridization with a nonselective AT1 receptor riboprobe indicated that the highest levels of AT1 mRNA were in the outer medullary vasa recta and cortical glomeruli with additional diffuse labeling of the cortex and outer medulla, consistent with labeling of tubular elements. In contrast, in situ hybridization with the AT1 subtype selective probes revealed that AT1A receptor mRNA was primarily localized to the vasa recta and diffusely to the outer stripe of the outer medulla and the renal cortex.(ABSTRACT TRUNCATED AT 250 WORDS)


Endocrinology ◽  
2000 ◽  
Vol 141 (7) ◽  
pp. 2703-2706 ◽  
Author(s):  
Anders Juréus ◽  
Matthew J. Cunningham ◽  
Molly E. McClain ◽  
Donald K. Clifton ◽  
Robert A. Steiner

Galanin-like peptide (GALP), which was recently isolated from the porcine hypothalamus, shares sequence homology with galanin and binds with high affinity to galanin receptors. To study the distribution and regulation of GALP-expressing cells in the brain, we cloned a 120 base-pair cDNA fragment of rat GALP and produced an antisense riboprobe. In situ hybridization for GALP mRNA was then performed on tissue sections throughout the forebrain of adult ovariectomized female rats. We found GALP mRNA-containing cells in the arcuate nucleus (Arc), caudal dorsomedial nucleus, median eminence and the pituitary. Because GALP mRNA in the Arc appeared to overlap with the known distribution of leptin receptor mRNA, we tested the hypothesis that GALP expression is regulated by leptin. Using in situ hybridization, we compared the number of GALP mRNA-containing cells among groups of rats that were fed ad lib or fasted for 48 h and treated with either leptin or vehicle. Fasting reduced the number of identifiable cells containing GALP mRNA in the Arc, whereas the treatment of fasted animals with leptin produced a 4-fold increase in the number of cells expressing GALP message. The presence of GALP mRNA in the hypothalamus and pituitary and its regulation by leptin suggests that GALP may have important neuroendocrine functions, including the physiological regulation of feeding, metabolism, and reproduction.


Sign in / Sign up

Export Citation Format

Share Document