0000000000922942
AUTHOR
Flavia Mule'
“Intracellular events following P2Y receptor activation in murine colonic circular muscle”.
Relaxation induced by glucagon-like peptide-2 in mouse gastric preparation.
Mechanism of action of the betalain pigment indicaxanthin, purified from fruits of Opuntia ficus-indica, on mouse ileal motility in vitro.
Does GLP-2 receptor expression change dynamically in fed and fasted states?
Effects of vasostatin-1 on the mouse gastric mechanical activity.
GLUCAGON-LIKE PEPTIDE-1 MODULATES EXCITATORY CHOLINERGIC NEUROTRANSMISSION OF MOUSE DUODENUM AND COLON
The incretin Glucagon-like-peptide-1 (GLP-1) is produced by enterendocrine L cells of the small intestine. It delays gastric emptying and reduces intestinal transit by inhibiting vagal activity. To date, no evidences are available about a direct peripheral influence on gastrointestinal smooth muscle cells. The purpose of the present study was to investigate in vitro the effects of GLP-1 on the spontaneous and evoked mechanical activity of murine duodenum and colon, recording intraluminal pressure, index of the circular mechanical activity, and isometric tension, index of the longitudinal mechanical activity. In both intestinal segments GLP-1 (up to 1 μM) did not affect spontaneous mechanica…
Efficacia di Omalizumab in una bambina con sindrome autoinfiammatoria e orticaria cronica
Mechanisms involved in adenosine-induced relaxation of mouse colon
Tachykinergic neurotransmission is enhanced in duodenum from dystrophic (mdx) mice
1 Duodenal longitudinal muscle of mdx mice, an animal model for Duchenne muscular dystrophy, showed a decrease in the electrically evoked nonadrenergic, noncholinergic (NANC) inhibitory responses associated with a reduction of the participation of nitric oxide (NO). In this study, we investigated whether the impairment of NO could also lead to alterations in the NANC excitatory transmission. 2 Nerve-evoked responses consisted of an inhibitory phase followed, at the end of stimulation, by an excitatory response characterised by an increase in amplitude of the spontaneous contractions. In mdx mice, the amplitude of the nerve-evoked contractions was significantly higher than in normals. 3 N(om…
Modulatory role of cannabinoids on the spontaneous mechanical activity of mouse ileal longitudinal muscle. Acta Physiologica
Chronic treatment with GLP-2 (3-33) exacerbates glucose metabolism disorders in mice fed a high fat diet.
Cellular transduction mechanisms underlying P2Y receptor activation in mouse colonic muscle
Role of NK2 tachykinergic receptors in stomach of dystrophic (mdx) mice
Peripheral Glucagon-like peptide 2 administration inhibits food intake in mice: Analysis of the mechanism of action.
OBJECTIVE: Previously we showed that, in mice, peripheral administration of glucagon-like peptide 2 (GLP-2) or [Gly2]GLP-2, the degradation-resistant analogue of GLP-2, reduces food intake in the short term. The purposes of the present study were to compare the influence of [Gly2]GLP-2 with the anorectic effect induced by glucagon-like peptide 1 (GLP-1) and to analyze the mechanism of action responsible for GLP-2-induced effects. METHODS: Food intake was measured in mice, fasted for 16-18 h, at the first hour following peptide or vehicle intraperitoneally (i.p.) administration. The effects of GLP-2 (3-33), GLP-2 receptor (GLP-2R) antagonist, and exendin (9-39), GLP-1R antagonist were also e…
Insulin Nanogels: a New Strategy for the Treatment of Alzheimer’s Disease
A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signaling are involved in brain cognitive functions and their dysfunction is implicated in Alzheimer’s disease (AD) degeneration. Thus, administration of insulin could be a strategy for AD treatment. For this aim we have designed, synthesized and characterized a nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for AD. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation was chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility of the naked c…
INVOLVEMENT OF GUANINE-BASED PURINES IN THE MODULATION OF CHOLINERGIC TRANSMISSION IN MOUSE COLONIC PREPARATIONS
Flavonoid-induced gastric relaxation: structure-activity relationship and mechanism of action.
ADENOSINE IS A MODULATOR OF THE CONTRACTILITY OF THE DUODENAL LONGITUDINAL MUSCLE IN MICE
AT1 receptors mediate contractile effects of Angiotensin II on mouse colon
Angiotensin II (Ang II) is a potent smooth muscle contractile neurohumoral agonist via interaction with AT1 and AT2 receptors. Although these receptors are well expressed in the gut, very little research has been devoted to analysed the physiological role played by Ang II (and its receptors) in the regulation of gastrointestinal motility. The effects of Ang II on mouse proximal and distal colon contractility, the receptor subtypes involved were investigated in vitro, using the organ bath technique. Longitudinally-oriented segments from mouse proximal and distal colon displayed ongoing contractile activity, characterized by phasic contractions. Ang II induced a concentration-dependent muscul…
Obesità e resistenza all'insulina: due fattori di rischio per l'insorgenza della malattia di Alzheimer
Fisiologia e Biofisica delle cellule
Pharmacological characterization of Uracil nucleotide-sensitive P2Y receptors in mouse ileum
Since uracil nucleotide-preferring receptors, belonging to the P2Y receptor family and responding to either uridine triphosphate (UTP) or uridine diphosphate (UDP), have been proposed to be present at different cellular level in the gut, regulating various functions, we aimed to investigate whether their activation by uracil nucleotides may modulate the contractility of the intestinal muscle. Experiments were carried out in vitro, and the contractility of the longitudinal muscle from mouse ileum was recorded as changes of the isometric tension. UDP or UTP evoked a concentrationdependent, tetrodotoxin insensitive, contractile response. UDP effect was antagonized by suramin and by PPADS, P2 r…
Influence of glucagon-like peptide-2 on mouse proximal colon motility.
Defective dopaminergic control of contractility in colon from hypoxanthine‐guanine phosphoribosyltransferase deficient (HPRT‐) knockout mice
The glucagon-like Peptide-2
Multiple peptide hormones produced within the gastrointestinal system act also in the central nervous system and aid in the regulation of energy homeostasis and metabolism. The list of these peptides is progressively increasing and includes glucagon-like peptide 2 (GLP-2) as an anorexigenic factor. GLP-2 is released from enteroendocrine L-cells following food intake and its principal target is represented by the gastrointestinal tract. GLP-2 has been shown to be an important intestinotrophic factor that stimulates epithelial cell proliferation and inhibits apoptosis. GLP-2 increases intestinal blood flow and the activity and expression of epithelial brush-border digestive enzymes and nutrie…
Influence of cannabinoids on NANC neural transmission in mouse colon.
Prejunctional modulation by CB2 receptor agonists on cholinergic evoked responses in mouse stomach.
Mechanisms underlying nitric oxide inhibitory effects in mouse ileal longitudinal muscle
Inhibitory control of duodenal contractility by adenosine in mice
Prejunctional Modulation of Purinergic Neurotransmission by P2Y1 Receptors in Mouse Caecum
Relaxation induced by vasostatin 1 in mouse gastric preparations
A1 receptor-mediated modulatory effects of adenosine on the contractility in mouse ileum: characterization of signal transduction pathway
Functional analysis of the digestive tract in mdx mice
Adenosine negatively regulates duodenal motility in mice: role of A1 and A2a receptors .
Effects of glucagon-like peptide 1 on intestinal mechanical activity in mouse
Gastric relaxation induced by flavonoids: analysis of the underlying mechanisms.
GUANOSINE EFFECTS ON THE MOTOR ACTIVITY OF THE MOUSE STOMACH
Guanine-based purines are part of the purinergic system and recently have been shown to act as neuromodulators, interfering with acetylcholine release by enteric neurons in mouse colon. Due to the pivotal role played by enteric neurons in the control of gastrointestinal motility, the aim of the present study was to verify whether guanosine may affect gastric emptying and the mechanical tone, detected in vitro as changes in intraluminal pressure, of the isolated mouse stomach. Guanosine induced a TTX-insensitive concentration-dependent relaxation of isolated stomach, which at the maximal concentration tested (1 mM), reached about 60% of the relaxation induced by 1 mM isoproterenol. The inhib…
Guanine-based purines affects the enteric cholinergic neurotransmission via a mechanism not involving membrane receptors
Increasing evidence indicate that guanine-based purines, known as modulators of intracellular processes, can exert extracellular effects, raising the possibility of the existence of specific receptors for these compounds. We investigated if guaninebased purine receptors may be present in the rodent gastrointestinal tract modulating intestinal contractility, as the well known adenine-based purine receptors. Experiments were performed in vitro recording spontaneous and neurally-evoked contractile activity, as changes in isometric tension, in mouse distal colon circular muscle. Guanosine up to 3 mM or guanine up to 1 mM, did not affect the spontaneous mechanical activity, but they significantl…
Effects of chromogranin A 7-57 synthetic peptide on the spontaneous contractions of rat proximal colon
Glucagon-Like Peptide-1 Modulates Neurally-Evoked Mucosal Chloride Secretion in Guinea Pig Small Intestine In Vitro.
Glucagon-like peptide-1 (GLP-1) acts at the G protein-coupled receptor, GLP-1R, to stimulate secretion of insulin and to inhibit secretion of glucagon and gastric acid. Involvement in mucosal secretory physiology has received negligible attention. We aimed to study involvement of GLP-1 in mucosal chloride secretion in the small intestine. Ussing chamber methods, in concert with transmural electrical field stimulation (EFS), were used to study actions on neurogenic chloride secretion. ELISA was used to study GLP-1R effects on neural release of acetylcholine (ACh). Intramural localization of GLP-1R was assessed with immunohistochemistry. Application of GLP-1 to serosal or mucosal sides of fla…
Glucagon-like peptide-2: Gut signal and lipid parameters in obese mice
NANC inhibitory neurotransmission in mouse isolated stomach: Involvement of nitric oxide, ATP and vasoactive intestinal polypeptide
1. The neurotransmitters involved in NANC relaxation and their possible interactions were investigated in mouse isolated stomach, recording the motor responses as changes of endoluminal pressure from whole organ. 2. Field stimulation produced tetrodotoxin-sensitive, frequency-dependent, biphasic responses: rapid transient relaxation followed by a delayed inhibitory component. 3. The inhibitor of the synthesis of nitric oxide (NO), L-NAME, abolished the rapid relaxation and significantly reduced the slow relaxation. Apamin, blocker of Ca 2+-dependent K + channels, or ADPβS, which desensitises P 2y purinoceptors, reduced the slow relaxation to 2-8 Hz, without affecting that to 16-32 Hz or the…
Evidence for region-specific effects of glucagone-like peptide-2 in mouse stomach
Ultrastructural changes in the Interstitials Cells of Cajal and gastric dysrhythmias in mice lacking full-length dystrophin (mdx mice)
At least two populations of c-kit positive interstitial cells of Cajal (ICC) lie in the gastric wall, one located at the myenteric plexus level has a pace-making function and the other located intramuscularly is intermediary in the neurotransmission and regenerates the slow waves. Both of these ICC sub-types express full-length dystrophin. Mdx mice, an animal model lacking in full-length dystrophin and used to study Duchenne muscular dystrophy (DMD), show gastric dismotilities. The aim of the present study was to verify in mdx mice whether: (i) gastric ICC undergo morphological changes, through immunohistochemical and ultrastructural analyses; and (ii) there are alterations in the electrica…
Inducible nitric oxide synthase participates to the evoked relaxation in dystrophic (mdx) gastric preparations
Modulation of the spontaneous mechanical activity of mouse ileum: interplay between cannabinoids and purines
Activation of P2Y receptors by ATP and by its analogue, ADPbetaS, triggers two calcium signal pathways in the longitudinal muscle of mouse distal colon.
Our previous research showed that ATP and adenosine 5'-O-2-thiodiphosphate (ADPbetaS) induce contractile effects in the longitudinal muscle of mouse distal colon via activation of P2Y receptors which are not P2Y(1) or P2Y(12) subtypes. This study investigated the nature of the P2Y receptor subtype(s) and the mechanisms leading to the intracellular calcium concentration increase necessary to trigger muscular contraction. Motor responses of mouse colonic longitudinal muscle to P2Y receptor agonists were examined in vitro as changes in isometric tension. ATP or ADPbetaS induced muscular contraction, which was not affected by P2Y(11) or P2Y(13) selective antagonists. Calcium-free solution or th…
Effects of menthol on mouse gastric mechanical activity
GABA and its receptors in the enteric nervous system of the gastrointestinal tract.
Altered electrical activity in duodenal muscle cells from mdx (dystrophic) mice.
Postnatal developmental changes in the dopaminergic signaling in mouse gut
The presence of dopamine-containing neurons in the enteric nervous system has been described, but it is far to be clear their role in the modulation of gut motility. Moreover, ontogenetic studies shows that dopaminergic neurons are late-developing neurons, arising perinatally, but there are no informations if dopaminergic signaling may undergo to developmental changes after birth, as demonstrated for other signaling. Thus, using a pharmacological approach, we examined, in vitro, the role of dopaminergic neurons in the regulation of duodenal contractility in neonatal mice (≤48 h postnatal) compared to the adults. Transcripts for all dopaminergic receptors were detected in mouse duodenum at e…
Effects of CB1 and CB2 receptor agonists on the neurally-evoked responses in mouse stomach.
Intracellular mechanisms involved in NO-induced relaxation of mouse ileum
Myocardial and coronary functions of glucagon-like peptide-2 in the rat heart.
Insulin Nanogel as New Strategy for the Treatment of Alzheimer’s Disease
A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signaling are involved in brain cognitive functions and their dysfunction is implicated in neuronal degeneration associated with Alzheimer's disease (AD). Thus, the administration of insulin to the brain could be a strategy for the prevention and treatment of AD disease. With this aim, we have designed, synthesized and characterized a nanogel system (NG) that can be used as substrate for the conjugation of insulin and/or fluorescent molecules relevant for their characterization. In particular, a carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system, has been produced by ionizing radiation starting from th…
ATP contributes to excitatory enteric neurotransmission in the longitudinal muscle of mouse distal colon.
Alterations of intestinal transit and fecal output in dystrophic mdx mice.
Relaxation Induced By Guanosine in Mouse Stomach
Guanine-based purines are part of the purinergic system and recently have been shown to act as neuromodulators, interfering with acetylcholine release by enteric neurons in mouse colon. Due to the pivotal role played by enteric neurons in the control of gastrointestinal motility, the aim of the present study was to verify whether guanosine may affect gastric emptying and the mechanical tone, detected in vitro as changes in intraluminal pressure, of the isolated mouse stomach. Guanosine induced a TTX-insensitive concentration-dependent relaxation of isolated stomach, which at the maximal concentration tested (1 mM), reached about 60% of the relaxation induced by 1 µM isoproterenol. The inhib…
Increased calcium influx is responsible for the sustained mechanical tone in colon from dystrophic (mdx) mice
Background & Aims: Proximal colon from dystrophic mice develops spontaneous tone increment, but the mechanisms involved in its development have not been investigated. This study examined whether alterations in the properties of cell membrane calcium channels and/or sarcoplasmic reticular (SR) Ca2+-adenosine triphosphatase (ATPase) contribute to tone development. Methods: Effects of calcium-free solution, nifedipine, pinaverium (calcium channel blockers), and cyclopiazonic acid (CPA; SR Ca2+-ATPase inhibitor) on the contractile activity of colon from mdx and control mice were determined. Results: Calcium-free solution abolished spontaneous contractions in both preparations, but decreased the…
Comparison of pacing activity in duodenal muscle cells from and mdx (dystrophic) mice.
POSTNATAL MATURATION OF SEROTONIN SIGNALING SYSTEM IN MOUSE DUODENUM
BACKGROUND AND AIMS: A plethora of study in animal neurodevelopmental models demonstrate that in central nervous system (CNS) temporal differences occur in the maturation of different neurotransmitter systems (Goldman-Rakic & Brown, 1982, Ehrlich et al., 2013). Although significant advances have been made in understanding the modifications in CNS, only primarily descriptive studies about the changes taking place in enteric nervous system (ENS), main regulator of gastrointestinal (GI) functions, have been underway. As the other organ systems, digestive system is still developing and maturing after birth and thus it is possible to speculate that the changes in the chemical coding of ENS may o…
Role of Endogenous GLP-2 in the Intestinal Adaptation to a Chronic High Fat Diet
P2Y-mediated contractile responses in the longitudinal muscle of mouse distal colon: distinct signaling pathways
Is guanine a regulator of contractility in rat colon?
Effects of exogenous tachykinins on gastric tone of normal and mdx mice: a comparative analysis
"A1 receptors mediate the inhibitory effects of adenosine on the contractility in mouse ileum.”
Peripheral motor effects of glucagon-like peptide-1 in mouse intestine.
Agonist-specific Ca2+ signaling at P2Y receptors
POSTNATAL DEVELOPMENT OF THE 5-HYDROXYTRYPTAMINE (5-HT) SIGNALING SYSTEM IN THE MOUSE
Evidence for region-specific effects of glucagon-like peptide-1 in mouse stomach.
Glucagon-like peptidi-2 action and GLP-2 receptor expression in stomach of mice fed a high fat diet or fasted.
Ruolo del peptide glucagone simile-2 nell'adattamento intestinale ad una dieta iperlipidica
Effects of glucagon-like peptide-2 on mouse gastric tone
GLP-2: a potential signal for improving glycemic control
Peripheral motor action of glucagon like peptide-1 through enteric neuronal receptors.
Effects of cannabinoids on spontaneous mechanical activity of mouse ileal longitudinal muscle.
Changes in the contractility of colon from hypoxanthine-guanine phosphoribosyltransferase (HPRT) knockout mice (Lesch-Nyhan disease)
Role of the cromogranin A-derived fragments on the spontaneous contractions of rat proximal colon
Modulatory role of glucagon-like peptidi-1 on neurally-evoked mucosal chloride secretion in the guinea-pig ileum.
Interplay between cannabinoids and purines in the modulation of the spontaneous mechanical activity of mouse ileum.
The emerging myocardial and coronary action of Glucagon-derived peptide-2.
Influence by glucagon-like peptide-2 (GLP-2) on spontaneous mechanical activity and electrically-evoked cholinergic contractions in mouse proximal colon.
Adenosine receptor subtypes in mouse colon
Peripheral motor action of glucagon-like peptide-1 through enteric neuronal receptors.
Background Glucagon-like peptide-1 (GLP-1) is a proglucagon-derived peptide expressed in the enteroendocrine-L cells of small and large intestine and released in response to meal ingestion. Glucagon-like peptide-1 exerts inhibitory effects on gastrointestinal motility through vagal afferents and central nervous mechanisms; however, no data is available about a direct influence on the gastrointestinal wall. Our aim was to investigate the effects of GLP-1 on the spontaneous and evoked mechanical activity of mouse duodenum and colon and to identify the presence and distribution of GLP-1 receptors (GLP-1R) in the muscle coat. Methods Organ bath recording technique and immunohistochemistry were …