Gastric emptying of enterally administered liquid meal in conscious rats and during sustained anaesthesia

Qualls‐Creekmore, Emily; Tong, Melissa; Holmes, Gregory M.

doi:10.1111/j.1365-2982.2009.01393.x

Cited by 22 publications

(16 citation statements)

References 43 publications

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“…The advent and continuous advancement of imaging, optogenetic, and pharmacogenetic techniques allows for the selective activation or inhibition of specific neuronal subpopulations or pathways; this may prove to be particularly useful and valuable when dealing with brainstem and other central neurocircuits, given their extensive, and often intermingled, afferent and efferent connections. The standardization of experimental techniques between groups of researchers would also be advantageous in comparing experimental outcomes; note, for example, the differential effects of anesthetics on gastric emptying rates (384). Species and strain differences may also be critically important in determining experimental outcomes; Sprague-Dawley, but not Fisher 344 rats, for example, show habituation to the GI effects of stress (25, 206).…”

Section: Discussionmentioning

confidence: 99%

Central Nervous System Control of Gastrointestinal Motility and Secretion and Modulation of Gastrointestinal Functions

Browning

Travagli

2014

Comprehensive Physiology

407

364

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Although the gastrointestinal (GI) tract possesses intrinsic neural plexuses that allow a significant degree of autonomy over GI functions, the central nervous system (CNS) provides extrinsic neural inputs that regulate, modulate, and control these functions. While the intestines are capable of functioning in the absence of extrinsic inputs, the stomach and esophagus are much more dependent upon extrinsic neural inputs, particularly from parasympathetic and sympathetic pathways. The sympathetic nervous system exerts a predominantly inhibitory effect upon GI muscle and provides a tonic inhibitory influence over mucosal secretion while, at the same time, regulates GI blood flow via neurally mediated vasoconstriction. The parasympathetic nervous system, in contrast, exerts both excitatory and inhibitory control over gastric and intestinal tone and motility. Although GI functions are controlled by the autonomic nervous system and occur, by and large, independently of conscious perception, it is clear that the higher CNS centers influence homeostatic control as well as cognitive and behavioral functions. This review will describe the basic neural circuitry of extrinsic inputs to the GI tract as well as the major CNS nuclei that innervate and modulate the activity of these pathways. The role of CNS-centered reflexes in the regulation of GI functions will be discussed as will modulation of these reflexes under both physiological and pathophysiological conditions. Finally, future directions within the field will be discussed in terms of important questions that remain to be resolved and advances in technology that may help provide these answers.

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Section: Discussionmentioning

confidence: 99%

Central Nervous System Control of Gastrointestinal Motility and Secretion and Modulation of Gastrointestinal Functions

Browning

Travagli

2014

Comprehensive Physiology

407

364

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“…13 C]-octanoic acid breath test was performed 1 wk before the 6-OHDA microinjection (baseline) and weekly for 4 wk after (SNpc degeneration) using procedures described previously (44). Briefly, rats were fasted overnight with ad libitum access to water before being placed in metabolic chambers (ϳ7-l capacity) under a continuous flow of fresh air (0.65-0.70 l/min) to maintain the rate of CO 2 at 0.5%.…”

Section: Measurement Of Gastric Emptying Using [ 13 C]-octanoic Acid mentioning

confidence: 99%

Gastric dysregulation induced by microinjection of 6-OHDA in the substantia nigra pars compacta of rats is determined by alterations in the brain-gut axis

Toti

Travagli

2014

American Journal of Physiology-Gastrointestinal and Liver Physi

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Toti L, Travagli RA. Gastric dysregulation induced by microinjection of 6-OHDA in the substantia nigra pars compacta of rats is determined by alterations in the brain-gut axis. Am J Physiol Gastrointest Liver Physiol 307: G1013-G1023, 2014. First published October 2, 2014; doi:10.1152/ajpgi.00258.2014.-Idiopathic Parkinson's disease (PD) is a late-onset, chronic, and progressive motor dysfunction attributable to loss of nigrostriatal dopamine neurons. Patients with PD experience significant gastrointestinal (GI) issues, including gastroparesis. We aimed to evaluate whether 6-hydroxy-dopamine (6-OHDA)-induced degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNpc) induces gastric dysmotility via dysfunctions of the brain-gut axis. 6-OHDA microinjection into the SNpc induced a Ͼ90% decrease in tyrosine hydroxylase-immunoreactivity (IR) on the injection site. The [13 C]-octanoic acid breath test showed a delayed gastric emptying 4 wk after the 6-OHDA treatment. In control rats, microinjection of the indirect sympathomimetic, tyramine, in the dorsal vagal complex (DVC) decreased gastric tone and motility; this inhibition was prevented by the fourth ventricular application of either a combination of ␣1-and ␣2-or a combination of D1 and D2 receptor antagonists. Conversely, in 6-OHDA-treated rats, whereas DVC microinjection of tyramine had reduced effects on gastric tone or motility, DVC microinjection of thyrotropin-releasing hormone induced a similar increase in motility as in control rats. In 6-OHDA-treated rats, there was a decreased expression of choline acetyl transferase (ChAT)-IR and neuronal nitric oxide synthase (NOS)-IR in DVC neurons but an increase in dopamine-␤-hydroxylase-IR in the A2 area. Within the myenteric plexus of the esophagus, stomach, and duodenum, there were no changes in the total number of neurons; however, the percentage of NOS-IR neurons increased, whereas that of ChAT-IR decreased. Our data suggest that the delayed gastric emptying in a 6-OHDA rat model of PD may be caused by neurochemical and neurophysiological alterations in the brain-gut axis.brainstem; gastric motility; immunohistochemistry; Parkinson's disease IDIOPATHIC PARKINSON'S DISEASE (PD) is generally considered a movement disorder characterized by bradykinesia, rigidity, tremor, and gait/postural disorders related to the severe degeneration of the dopaminergic neurons in the substantia nigra pars compacta (SNpc) of the basal ganglia. Although the movement disorder has dominated the attention of clinicians and researchers, it is becoming increasingly recognized that PD also involves a prominent nonmotor pathology. In fact, patients with PD experience a remarkably broad spectrum of prodromic nonmotor symptoms that include sleep disorders, orthostatic hypotension, and gastrointestinal (GI) dysfunctions, all of which add significantly to the overall disability caused by PD (9,22,26,33,38,42).GI symptoms, such as dysphagia, nausea, delayed gastric emptying and dysmotility, and constipation, often precede ...

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“…In addition, the stimulation induced by central vagal activation and ghrelin or other transmitters initially observed in urethane anesthetized rats have been largely reproduced in conscious rats [18,21,63,64]. However urethane results in the activation of sympathetic outflow [8], hyperglycemia [27] and gastric somatostatin release [71] that can impact on gastric motor function [51]. Therefore it will be relevant to expand this non-invasive pressure microsensor method under other anesthetic conditions (inactin, pentobarbital) also used to record gastric motility.…”

Section: Discussionmentioning

confidence: 99%

Modulation of gastric motility by brain-gut peptides using a novel non-invasive miniaturized pressure transducer method in anesthetized rodents

et al. 2011

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Acute in vivo measurements are often the initial, most practicable approach used to investigate the effects of novel compounds or genetic manipulations on the regulation of gastric motility. Such acute methods typically involve either surgical implantation of devices or require intragastric perfusion of solutions, which can substantially alter gastric activity and may require extended periods of time to allow stabilization or recovery of the preparation. We validated a simple, noninvasive novel method to measure acutely gastric contractility, using a solid-state catheter pressure transducer inserted orally into the gastric corpus, in fasted, anesthetized rats or mice. The area under the curve of the phasic component (pAUC) of intragastric pressure (IGP) was obtained from continuous manometric recordings of basal activity and in responses to central or peripheral activation of cholinergic pathways, or to abdominal surgery. In rats, intravenous ghrelin or intracisternal injection of the thyrotropin-releasing hormone agonist, RX-77368, significantly increased pAUC while coeliotomy and caecal palpation induced a rapid onset inhibition of phasic activity lasting for the 1-h recording period. In mice, RX-77368 injected into the lateral brain ventricle induced high-amplitude contractions, and carbachol injected intraperitoneally increased pAUC significantly, while coeliotomy and caecal palpation inhibited baseline contractile activity. In wild-type mice, cold exposure (15-min) increased gastric phasic activity and tone, while there was no gastric response in corticotorpin releasing factor (CRF)-over-expressing mice, a model of chronic stress. Thus, the novel solid-state manometric approach provides a simple, reliable means for acute pharmacological studies of gastric motility effects in rodents. Using this method we established in mice that the gastric motility response to central vagal activation is impaired under chronic expression of CRF.

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Gastric emptying of enterally administered liquid meal in conscious rats and during sustained anaesthesia

Cited by 22 publications

References 43 publications

Central Nervous System Control of Gastrointestinal Motility and Secretion and Modulation of Gastrointestinal Functions

Central Nervous System Control of Gastrointestinal Motility and Secretion and Modulation of Gastrointestinal Functions

Gastric dysregulation induced by microinjection of 6-OHDA in the substantia nigra pars compacta of rats is determined by alterations in the brain-gut axis

Modulation of gastric motility by brain-gut peptides using a novel non-invasive miniaturized pressure transducer method in anesthetized rodents

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