Structural and immunoendocrine remodeling in gut, pancreas and thymus in weaning rats fed powdered milk diets rich in Maillard reactants.

Western diet is extending worldwide and suspected to be associated with various metabolic diseases. Many food products have skim milk powder added to it and, during processing, lactose reacts with milk proteins and Maillard reaction products (MRPs) are formed. Dietary MRPs are suggested risk factors for metabolic dysregulation, but the mechanisms behind are still enigmatic. Here we describe that weaning rats fed diets rich in MRPs are affected in both their immune and endocrine systems. Marked structural changes in pancreas, intestine and thymus are noted already after 1 week of exposure. The pancreatic islets become sparser, the intestinal mucosa is thinner, and thymus displays increased apoptosis and atrophy. Glucagon- like peptide-1 (GLP-1) seems to play a key role in that the number of GLP-1 expressing cells is up-regulated in endocrine pancreas but down-regulated in the intestinal mucosa. Further, intestinal GLP-1-immunoreactive cells are juxta positioned not only to nerve fibres and tuft cells, as previously described, but also to intraepithelial CD3 positive T cells, rendering them a strategic location in metabolic regulation. Our results suggest dietary MRPs to cause metabolic disorders, dysregulation of intestinal GLP-1- immunoreactive cells, arrest in pancreas development and thymus atrophy.

Usability of RemindMe - An Interactive Web-Based Mobile Reminder Calendar: A Professional's Perspective.

AIM: The aim of the study was to examine the usability of an interactive web-based mobile reminder calendar (RemindMe) developed for supporting individuals in organizing, planning and executing activities in everyday life, from the perspectives of professionals. METHODS AND MATERIAL: Eleven professionals working in community services evaluated the usability of RemindMe in their clinical practice. Data were collected using semi-structured interviews and analysed with inductive qualitative analysis. RESULTS: The professionals perceived that RemindMe was useful, easy to use, and intuitive. There was a need among professionals for a web-based reminder calendar that requires the active acknowledgement of reminders. RemindMe's feedback system offering self-monitored information based on the user's interaction with the system supported the professionals in discussions, evaluation, and follow-up based on the needs of the persons with cognitive impairments. CONCLUSION: The results indicate that RemindMe may be potentially useful to professionals who provide support to individuals with cognitive impairments. However, further research is needed to evaluate experience of using RemindMe from the perspective of individuals with cognitive impairments.

Mapping of TLR5 and TLR7 in central and distal human airways and identification of reduced TLR expression in severe asthma.

BACKGROUND: The toll-like receptors, TLR5 and TLR7, have recently been proposed in asthma immunopathogenesis. While supporting data come from animal or in vitro studies, little is known about TLR5 and TLR7 expression in human asthmatic airways. METHODS: Advanced immunohistochemical mapping of TLR5 and TLR7 was performed on bronchial and transbronchial biopsies from healthy individuals and patients with moderate and severe asthma. RESULTS: TLR5 was identified in multiple structural cells; bronchial epithelium, alveolar type II pneumocytes, plasma cells, macrophages and neutrophils. Contrary to bronchial TLR5, which had a basolateral expression, alveolar TLR5 had polarized apical localization. Patients with severe asthma had decreased total and epithelial TLR5 expression compared to controls and moderate asthmatics (P < 0.001). TLR7 expression was found in several structural cells and asthma-related immune cells. Whereas TLR7 expression was decreased in severe asthmatics (P < 0.001), nerve-associated TLR7 increased (P = 0.035). Within the asthma groups, both TLR5 and TLR7 expression correlated with multiple lung function parameters. CONCLUSIONS: Our results reveal broad expression patterns of TLR5 and TLR7 in the lung and that the expression is decreased in severe asthma. Hence, severe asthmatics may suffer from insufficient TLR signalling during viral or bacterial infections leading to poor and impaired defence mechanisms.

Enhanced beta cell function and anti-inflammatory effect after chronic treatment with the dipeptidyl peptidase-4 inhibitor vildagliptin in an advanced-aged diet-induced obesity mouse model.

AIMS/HYPOTHESIS: Studies have shown that dipeptidyl peptidase-4 (DPP4) inhibitors stimulate insulin secretion and increase beta cell mass in rodents. However, in these models hyperglycaemia has been induced early on in life and the treatment periods have been short. To explore the long-term effects of DPP4 inhibition on insulin secretion and beta cell mass, we have generated a high-fat diet (HFD)-induced-obesity model in mice of advanced age (10 months old). METHODS: After 1 month of HFD alone, the mice were given the DPP4 inhibitor vildagliptin for a further 11 months. At multiple time points throughout the study, OGTTs were performed and beta cell area and long-term survival were evaluated. RESULTS: Beta cell function and glucose tolerance were significantly improved by vildagliptin with both diets. In contrast, in spite of the long treatment period, beta cell area was not significantly different between vildagliptin-treated mice and controls. Mice of advanced age chronically fed an HFD displayed clear and extensive pancreatic inflammation and peri-insulitis, mainly formed by CD3-positive T cells, which were completely prevented by vildagliptin treatment. Chronic vildagliptin treatment also improved survival rates for HFD-fed mice. CONCLUSIONS/INTERPRETATION: In a unique advanced-aged HFD-induced-obesity mouse model, insulin secretion was improved and the extensive peri-insulitis prevented by chronic DPP4 inhibition. The improved survival rates for obese mice chronically treated with vildagliptin suggest that chronic DPP4 inhibition potentially results in additional quality-adjusted life-years for individuals with type 2 diabetes, which is the primary goal of any diabetes therapy.

Effect of feeding colostrum versus exogenous immunoglobulin G on gastrointestinal structure and enteric nervous system in newborn pigs.

Colostrum is an indispensable source of antibodies (IgG) protecting the newborn pig against infection. We studied the effect of feeding colostrum and purified IgG on early structure and development of the gastrointestinal tract (GIT). Newborn littermate pigs were fed either colostrum, an elemental diet (ED), or an ED supplemented with purified serum IgG (ED + IgG) for 24 h or then only ED up to 72 h. Afterwards, pigs were slaughtered. Colostrum-fed pigs or ED supplemented with IgG (ED + IgG) increased thickness (P < 0.001) of stomach mucosa and muscularis (P < 0.05) compared to the ED group not receiving IgG. Feeding an ED supplemented with IgG improved morphology of the GIT towards that of colostrum-fed piglets and indicates a beneficial effect of IgG on GIT development in neonatal pigs. Immunohistochemical studies indicate that ED feeding may influence the expression of nitric oxide synthase in jejunal myenteric (but not submucous) neurons of newborn pigs.

Estrogen regulates DNA synthesis in human gingival epithelial cells displaying strong estrogen receptor ß immunoreactivity.

BACKGROUND AND OBJECTIVE: Estrogen acts via estrogen receptor (ER) α and ß. The expression pattern of ERs and their importance in gingival tissues are not fully understood. In this study, we investigate gingival ER expression and effects of estrogen on gingival epithelial cell proliferation. MATERIAL AND METHODS: Gingival biopsies were obtained from both healthy and diseased sites in three male and three female subjects. Expression of ERα and ß was determined by immunohistochemistry. Effects of 17ß-estradiol (E(2) ) on cell proliferation, monitored by measuring DNA synthesis, were studied in cultured human gingival epithelial HGEPp.05 cells. RESULTS: Estrogen receptor ß, but not ERα, immunoreactivity was demonstrated in nuclei of epithelial cells in all layers of the gingival epithelium, but also in cells of the lamina propria. No differences were observed between male and female subjects. The same pattern, i.e. high ERß expression but no ERα expression, was observed in both healthy and diseased sites within each individual. No differences in the intensity of the ERß immunoreactive signal and the number of ERß-positive nuclei were observed between healthy and diseased gingiva. Treatment with a physiological concentration of E(2) (10 nm) had no effect on DNA synthesis in ERß- and ERα-expressing HGEPp.05 cells. In contrast, E(2) at high concentrations (500 nm and 10 µm) reduced DNA synthesis by 60-70%. CONCLUSION: Human gingival epithelial cells display strong ERß but low ERα immunoreactivity both in vivo and in culture. Estrogen attenuates gingival epithelial cell DNA synthesis at high but not low concentrations, suggesting a concentration-dependent mechanism.

CART-peptide immunoreactivity in enteric nerves in patients with Hirschsprung's disease.

AIMS: Cocaine- and amphetamine-regulated transcript (CART)-peptide is found in the brain and participates in the control of feeding behavior. It is also expressed in the peripheral nervous system and is suggested to have neuromodulatory and/or neurotrophic effects in rat intestine. The aims of this study were to investigate the presence of CART-peptide in the normal ganglionic as well as aganglionic intestine from patients with Hirschsprung's disease and the peptide's possible coexistence with other neurotransmitters. METHODS: Intestinal specimens from nine patients with Hirschsprung's disease were examined using immunohistochemistry. A double immunostaining technique was used in order to elucidate the presence of CART-peptide in NOS and VIP-containing enteric neurons. RESULTS: In ganglionic intestine, CART-peptide was found in numerous nerve fibers, predominantly within the smooth muscle layers and in myenteric nerve cell bodies. A high degree of co-localization of CART with NOS and VIP was seen. Only very few CART immunoreactive nerve fibers and no nerve cell bodies were found in the aganglionic intestine. CONCLUSIONS: This is the first report on the presence of CART-peptide in the human intestine. In the ganglionic intestine CART was detected mainly in myenteric neurons, while only very few CART-IR nerve fibers were found in the aganglionic intestine. This, together with the coexistence of CART with NOS and VIP, indicates an intrinsic origin of the CART-containing neurons and suggests that CART may influence NO and VIP-induced effects.

Role of vasoactive intestinal peptide and inflammatory mediators in enteric neuronal plasticity.

Complex circuits involving both local intrinsic neurones (i.e. enteric nervous system; ENS) and extrinsic neurones achieve nervous control of digestive functions. The ENS is comprised of many functionally different types of neurons: sensory neurons, interneurons and secreto-motor neurons. Each neuronal population is required to manifest local reflex behavior and is central to the regulation of both motor and secretory activities. It must be emphasized, however, that not only muscle and secretory cells but also other intestinal cells are targeted by enteric neurones, i.e. endocrine cells, interstitial cells of Cajal, immune cells, blood vessels and enteric glia. In addition to the ENS the gastrointestinal tract receives an extrinsic innervation by sympathetic, parasympathetic and sensory fibres. Neuronal projections from the intestine to prevertebral ganglia also exist. Taken together, the picture of a complex nervous regulation of digestive functions highly integrated with the central nervous system and the rest of the autonomic nervous system has emerged. The ENS is adaptive and plastic, but also vulnerable, system and ENS disturbances may be of pathogenic importance in functional bowel disease. In particular the interplay between the enteric neurones and the immune cells is suggested to be of crucial importance. The review discusses possible roles of the mediators vasoactive intestinal peptide (VIP) and prostanoids in ENS plasticity in response to injury and inflammation.

Cocaine- and amphetamine-regulated transcript (CART) is expressed in several islet cell types during rat development.

Cocaine- and amphetamine-regulated transcript (CART) is an anorexigenic peptide widely expressed in the central and peripheral, including the enteric, nervous systems. CART is also expressed in pituitary endocrine cells, adrenomedullary cells, islet somatostatin cells, and in rat antral gastrin cells. We used immunocytochemistry (IHC) and in situ hybridization (ISH) to study CART expression in developing rat pancreas. We also examined co-expression of CART and islet hormones and developmental markers and the effect of CART on proliferation using clonal insulin cells (INS-1 832/13). A major portion of each of the islet cell types, except the ghrelin cells, expressed CART during a period before and around birth. Two weeks postnatally, CART expression was restricted to somatostatin cells. Pre- and early postnatally, many of the CART-expressing cells co-expressed cytokeratin 20 (CK20), a marker of duct cells and islet precursor cells, the trophic hormone gastrin, and a smaller subpopulation also harbored the proliferation marker Ki67. CART was also expressed in pancreatic nerve fibers, both sensory and autonomic, and in ganglion nerve cell bodies. Although highly expressed in the developing islets, CART did not affect proliferation of INS-1 cells. We have demonstrated that CART is expressed in several islet cell types during rat development but is restricted to somatostatin cells and neurons in the adult rat.

Immunocytochemical demonstration of estrogen receptor beta in human periodontal ligament cells.

Two transcription associated estrogen receptor (ER) subtypes have been identified and named ERalpha and ERbeta. In the present study we investigate the expression of these ER subtypes in cultured human periodontal ligament (PDL) cells by immunocytochemistry. ERbeta immunoreactivity was observed in the nuclei of about 40% of the PDL cells, while no ERalpha immunoreactivity was detected. In human breast cancer MCF-7 cells, serving as positive controls, both ERalpha and ERbeta immunoreactivities were demonstrated. No immunoreactivity was observed after omission of the primary antibodies. This study suggests that estrogen acts on gene transcription preferentially via ERbeta in human PDL cells.

Cocaine- and amphetamine-regulated transcript: distribution and function in rat gastrointestinal tract.

Cocaine- and amphetamine-regulated transcript (CART) peptide, originally isolated from brain, is also expressed in the peripheral nervous system. The distribution, origin and projections of CART-expressing enteric neurones by immunocytochemistry and in situ hybridization in rat gastrointestinal (GI) tract were studied. Possible motor functions of CART were studied in vitro using longitudinal muscle strips from stomach, ileum and colon. Cocaine- and amphetamine-regulated transcript peptide was found in numerous myenteric neurones throughout the GI tract while CART-expressing submucous neurones were scarce. Cocaine- and amphetamine-regulated transcript was also expressed in the antral gastrin cells. Myenteric CART-expressing neurones in both small and large intestine issued short descending projections. In atrophic ileum, CART mRNA-expressing neurones increased in number while neurones containing CART peptide decreased. In hypertrophied ileum, no change in CART peptide or CART mRNA containing myenteric neurones was detected. Cocaine- and amphetamine-regulated transcript 55-102 (10(-9)-10(-7) mol L-1) did not induce any contractile or relaxatory responses in the muscle strips, neither did it affect responses induced by vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide or neuronal stimulation. In colonic, but not in ileal, strips addition of CART attenuated nitric oxide (NO) donor-induced relaxations. Although CART does not seem to play a pivotal role in classic neurotransmission to the longitudinal muscle, it may serve a modulatory role in NO transmission. It may, moreover, be involved in intestinal adaptation, and an additional hormonal role is also possible.

Local infusion of the nitric oxide donor Sin-1 after angioplasty. Effects on intimal hyperplasia in porcine coronary arteries.

PURPOSE: To investigate the development of intimal hyperplasia in response to percutaneous transluminal coronary angioplasty (PTCA) followed by local delivery of the nitric oxide (NO) donor 3-morpholino-sydnonimine (SIN-1). MATERIAL AND METHODS: Overdilation PTCA was performed in coronary arteries in 20 healthy pigs. One of the dilated segments was additionally treated with local delivery of SIN-1 for 10 min. Segments distal to the treated part of the arteries served as controls. Arteries were radiographically depicted and analyzed after 1 and 8 weeks for actin, myosin and intermediate filaments (IF), nitric oxide synthetase (NOS) and histological evaluation. RESULTS: Segments treated with PTCA+SIN-1 showed a significantly (p=0.03) larger luminal diameter compared with PTCA only treated segments. The luminal loss after SIN-1 was not significant compared with the diameter prior to treatment. Endothelial NOS content was significantly lower in the PTCA+SIN-1 group compared with the PTCA group after 1 (p=0.03) and 8 weeks (p=0.013). IF/actin ratio after 1 week was significantly increased in PTCA-treated segments compared with untreated controls (p=0.004), and compared with PTCA+SIN-1-treated segments (p=0.004). CONCLUSION: PTCA-induced intimal hyperplasia was potently inhibited by local delivery of the NO donor SIN-1. Momentary events at the time of injury play a significant role in the development of intimal hyperplasia and long-lasting down-regulation of the endothelial NOS expression after SIN-1 exposure is suggested. The IF/actin ratio can be useful as an early marker of intimal hyperplasia.

Combined lack of estrogen receptors alpha and beta affects vascular iNOS protein expression.

Endothelial and vascular smooth muscle cells express both estrogen receptor (ER) alpha and beta. Recent findings indicate that vascular ER beta and ER alpha may substitute for one another. Here, we investigate vascular morphology, contractility and protein expression in intact aorta from adult (4 months old) female mice lacking both ER alpha and ER beta (DERKO). The body weights were 17% higher ( P<0.01) in DERKO than in wild-type mice. Vascular morphology, investigated in paraffin sections from aorta stained with hematoxylin-eosin or van Gieson, was identical in DERKO and wild-type mice. Endothelial cells were clearly visible in aorta of both DERKO and wild-type animals. Morphometric analysis of media thickness and wall to lumen ratio using a computerized image analyzing system demonstrated no differences between the two groups of mice. The vascular expression of endothelial nitric oxide synthase (eNOS, NOS III) and inducible nitric oxide synthase (iNOS, NOS II) was investigated using Western blotting. Aorta from both DERKO and wild-type mice expressed iNOS protein, but the iNOS expression was 3 times lower ( P<0.05) in DERKO compared to wild-type mice. No difference in eNOS protein level between the two groups of animals was observed. Force responses to noradrenaline, determined either in the absence or in the presence of the nitric oxide synthase inhibitor l-NAME and the cyclo-oxygenase inhibitor indomethacin, were unaffected by the lack of functional ER alpha/ER beta. In summary, combined lack of functional ER alpha and ER beta lowers the vascular expression of iNOS but has no effects on morphology, eNOS expression, and noradrenaline sensitivity in the intact aorta.

Sodium/iodide-symporter: distribution in different mammals and role in entero-thyroid circulation of iodide.

UNLABELLED: The sodium (Na+)/iodide (I-)-symporter (NIS) is abundantly expressed and accumulates iodide in thyroid follicular cells. The NIS is also found in extrathyroidal tissues, particularly gastric mucosa. Controversies exist on the localization of extrathyroidal NIS. We have studied the presence of both NIS peptide and NIS messenger RNA (mRNA) in the digestive tract and thyroid from different mammals. The role of gastric NIS is enigmatic and we aimed to unravel its possible involvement in iodide transport. METHODS: Distribution and expression of NIS were studied using immunocytochemistry and in situ hybridization. Iodide transport in the gastrointestinal tract was measured after oral or intravenous (i.v.) administration of 125I to rats with or without ligation of the pylorus. RESULTS: All thyroid follicular cells in rat and mouse expressed NIS, whereas a patchy staining was noted in man, pig and guinea-pig. Gastric mucosa surface epithelium in all species and ductal cells of parotid gland in guinea-pig, rat and mouse expressed NIS. In parietal cells and in endocrine cells of intestines and pancreas NIS immunoreactivity but no NIS mRNA was found. Studies of 125I uptake showed marked iodide transport from the circulation into the gastric lumen. CONCLUSIONS: The localization of NIS varies slightly among mammals. To establish expression of NIS in a particular cell type the need to correlate the presence of both NIS protein by immunocytochemistry and NIS mRNA by in situ hybridization is emphasized. An entero-thyroidal circulation of iodide mediated principally by gastric NIS, but possibly also by NIS in salivary glands is suggested.

Stimulation of vascular protein synthesis by activation of oestrogen receptor beta.

The objective of this study was to investigate the effects of oestrogen receptor (ER) beta activation on vascular protein synthesis and protein expression. Nuclear immunoreactivity towards ER beta was observed abundantly in vascular smooth muscle and endothelial cells of mouse aorta. No ER alpha-positive cell nuclei were observed. In aorta from ovariectomized mice, treatment with the selective ER beta agonist genistein (100 nM) for 24 h increased [(3)H]leucine incorporation by about 30%. This effect was prevented by the ER blocker ICI 182780 (10 microM). Although genistein treatment stimulated protein synthesis, it caused no change in total protein determined either by the Lowry method on tissue homogenate or by densitometric scanning of protein bands (10-220 kDa) separated by SDS-PAGE. Separation of [(35)S]methionine-labelled proteins by SDS-PAGE did not reveal the protein(s) stimulated by genistein. DNA synthesis was not affected by 100 nM genistein, suggesting that genistein-induced stimulation of protein synthesis is not part of a growth response. Protein expression, determined by SDS-PAGE, was similar in aorta from ER beta-knockout and wild-type mice, suggesting that expression of vascular proteins does not depend solely on a functional ER beta gene. We suggest that activation of vascular ER beta stimulates synthesis of proteins and that this response is not associated with vascular growth.

Platelet-derived growth factor receptors expressed in response to injury of differentiated vascular smooth muscle in vitro: effects on Ca2+ and growth signals.

Vascular smooth muscle cells (VSMCs) in the intact vascular wall are differentiated for contraction, whereas the response to vascular injury involves transition towards a synthetic phenotype, with increased tendency for proliferation. Platelet-derived growth factor (PDGF) is thought to be important for this process. We investigated expression and functional coupling of PDGF receptors (PDGFRs) alpha and beta in rat tail arterial rings kept in organ culture, in order to capture early events in the phenotypic transition. In freshly dissected rings no PDGFR immunoreactivity was found in medial VSMCs, whereas PDGFR alpha was detected in nerve fibres. After organ culture for 1-4 days PDGFR alpha and beta as well as phospholipase Cgamma2 (PLCgamma2), known to couple to PDGFR, were expressed in VSMCs within 100 microm of the cut ends. Calponin, a marker for the contractile phenotype, was decreased near the injured area, suggesting that cells were in transition towards synthetic phenotype. In these cells, which showed functional Ca2+-release from the sarcoplasmic reticulum, PDGF-AB (100 ng x mL(-1)) had no effect on [Ca2+]i, whereas cultured VSMCs obtained from explants of rat tail arterial rings responded to PDGF-AB with an increase in [Ca2+]i. However, PDGFR within the cultured rings coupled to growth signalling pathways, as PDGF-AB caused a tyrphostin AG1295-sensitive activation of extracellular signal-regulated kinases 1 and 2 and of [3H]-thymidine incorporation. Thus, early expression of PDGFR in VSMC adjacent to sites of vascular injury coincides with signs of dedifferentiation. These receptors couple to growth signalling, but do not activate intracellular Ca2+ release.

Increased expression of non-muscle myosin heavy chain-B in connective tissue cells of hypertrophic rat urinary bladder.

Expression of the non-muscle myosin heavy chain-B (NM-MHC-B, also denoted as the embryonic smooth muscle myosin heavy chain, SMemb) was examined in rat urinary bladder during growth in response to a partial urinary outflow obstruction. Following obstruction, the weight of the urinary bladder increased more than five-fold within 10 days. Immunohistochemistry with a polyclonal antiserum against the C-terminal sequence of NM-MHC-B revealed very few NM-MHC-B immunoreactive cells in the control urinary bladders. In hypertrophic bladders, the number of NM-MHC-B immunoreactive cells markedly increased. The majority of such cells were found in the interstitium surrounding smooth muscle bundles and also in the subserosal and submucosal layers. Western blot analysis showed that the NM-MHC-B expression was transient; the content of NM-MHC-B immunoreactive material had doubled 10 days after obstruction and then declined towards the control level after 6 weeks. Immunohistochemistry revealed co-localization of NM-MHC-B and vimentin within the same cells. NM-MHC-B did not co-localize with smooth muscle actin, suggesting that the source of NM-MHC-B is not a de-differentiated smooth muscle cell or myofibroblast but a non-muscle cell possibly reacting to tissue distension or stress. The NM-MHC-B-positive cells could have a role in the production of extracellular matrix and growth factors or be involved in modulation of spontaneous contractile activity.

Intestinal adaptation in atrophic rat ileum is accompanied by supersensitivity to vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide and nitric oxide.

BACKGROUND: Intestinal inactivity leads to atrophic changes and concomitant alterations in the expression of neurotransmitters in the enteric nervous system. In atrophic rat ileum neurones expressing vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) decrease in number while nitric oxide synthase (NOS) expressing neurones increase. Since little is known about functional changes accompanying intestinal atrophy the aim of the present study was to investigate relaxatory responses to VIP, PACAP-27 and nitric oxide (NO) in longitudinal smooth muscle from atrophic rat ileum. METHODS: To create a dysfunctional (atrophic) intestine, the distal 10 cm of rat ileum was surgically bypassed. In vitro experiments were carried out on longitudinal muscle strips from rat ileum having been sham-operated, one week or four weeks bypassed. RESULTS: The amplitudes of the relaxatory responses to PACAP-27, VIP and the NO-donor S-nitroso-N-acetylpenicillamine (SNAP), but not forskolin, were significantly increased in the one-week bypassed ileum. In the four-weeks bypassed ileum the VIP, PACAP-27, SNAP and forskolin evoked relaxations were of the same magnitude as those of the sham-operated. The augmented responses to both VIP and PACAP-27 could be blocked by pre-treatment with apamin while N(G)-nitro-L-arginine methyl ester (L-NAME) and tetrodotoxin were ineffective. In contrast to sham-operated and four-weeks bypassed ileum, cross-desensitization between VIP and PACAP-27 was noted after one week of bypass. CONCLUSION: Intestinal adaptation after bypassing the distal ileum of the rat includes a transient supersensitivity of the longitudinal muscle to the NO donor SNAP, VIP and PACAP-27. These augmented relaxatory responses may contribute to the hypomotility noted in inactive intestine.

Reinnervation of syngeneic pancreatico-duodenal grafts in rats.

BACKGROUND: Knowledge on the reinnervation of transplanted organs is scarce, and the aim of the study was therefore to evaluate to what degree syngeneic pancreas grafts were reinnervated in rats. METHODS: Syngeneic pancreatico-duodenal transplantations were performed in normoglycemic Wistar-Furth rats. Native and transplanted pancreas and duodenum were removed 4 or 40 weeks after implantation, and processed for indirect immunofluorescence using antibodies directed against vasoactive intestinal peptide, substance P (SP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY), tyrosine hydroxylase (TH), or the general neuronal marker protein gene product 9.5. RESULTS: Four weeks after transplantation a moderate to rich number of protein gene product 9.5-positive nerve fibers were found homogeneously distributed through the pancreas, probably representing the intrapancreatic nervous system, because the grafted pancreas lacked both a sympathetic (TH/NPY) and sensory (SP/CGRP) innervation 4 weeks after implantation. In a few of the animals there was a marked increase in SP-immunoreactive nerves (lacking CGRP), most conspicuous in the duodenal portion, both 4 and 40 weeks after transplantation probably secondary to a chronic pancreatitis. The fibers seemed to emanate from intrapancreatic ganglia and possibly also from enteric neurons in adjacent parts of the duodenum. A few scattered vasoactive intestinal peptide-containing nerve fibers probably also emanating from local ganglia could be seen throughout the grafted pancreas both 4 and 40 weeks after transplantation. At 40 weeks after transplantation sympathetic (TH- and NPY-positive) nerve fibers were regularly seen, whereas CGRP-positive nerve fibers were still virtually lacking in the pancreas. To trace the origin of the ingrowing nerve fibers, the tracer True Blue was injected into the grafted pancreas of some rats 38 weeks after transplantation, i.e., 2 weeks before killing. True Blue-labeled nerve cell bodies were numerous in the celiac ganglion (presumably sympathetic nerves) and few in dorsal root ganglia (sensory nerves). CONCLUSIONS: The data suggest that the transplanted rat pancreas becomes reinnervated by mainly sympathetic nerve fibers.

Expression and motor effects of secretin in small and large intestine of the rat.

Immunocytochemistry and in situ hybridization revealed abundant secretin expressing cells on duodenal villi with a gradual decrease throughout the small intestines of the rat. They were absent in pancreas, stomach and colon. Secretin caused relaxation of rat intestinal longitudinal muscle in vitro. Studies on colon revealed that the secretin-evoked response was unaffected by apamin, tetrodotoxin, L-NAME, VIP or PACAP pretreatment; secretin itself caused desensitization. Addition of VIP or PACAP when the secretin-evoked relaxation was maximal evoked a further relaxation suggesting the presence of distinct receptors. Secretin causes relaxation via activation of secretin receptors located on the smooth muscle and not via any of the related VIP/PACAP receptors.