Strain Gauge Force Transducers Research Articles

Determining Magnitudes of Forces at Known Locations through a Strain Gauge Force Transducer.

A novel strain gauge force transducer was developed to minimize the number of strain gauges needed to determine the magnitudes of loads when the locations are known. This innovative methodology requires only one strain gauge for each force magnitude desired, reducing the complexity and cost associated with traditional approaches. The theory was verified with laboratory experiments. Seven uniaxial strain gauges were attached to the underside of a simply supported, slender, aluminum beam. One or more loads were applied either directly atop strain gauges or in known positions between strain gauges. Experiments were conducted on several different single and double-load configurations to evaluate the extent of the new methodology which yielded average errors under 5% for the cases where loads were direct atop strain gauges and 6.6% for the cases where the loads were between strain gauges. These findings indicate the potential of this novel strain gauge force transducer to revolutionize load measurement in scenarios where load locations are predetermined.

CNS sites controlling the gastric pyloric sphincter: Neuroanatomical and functional study in the rat.

The pyloric sphincter receives parasympathetic vagal innervation from the dorsal motor nucleus of the vagus (DMV). However, little is known about its higher-order neurons and the nuclei that engage the DMV neurons controlling the pylorus. The purpose of the present study was twofold. First, to identify neuroanatomical connections between higher-order neurons and the DMV. This was carried out by using the transneuronal pseudorabies virus PRV-152 injected into rat pylorus torus and examining the brains of these animals for PRV labeling. Second, to identify the specific sites within the DMV that functionally control the motility and tone of the pyloric sphincter. For these studies, experiments were performed to assess the effect of DMV stimulation on pylorus activity in urethane-anesthetized male rats. A strain gauge force transducer was sutured onto the pyloric tonus to monitor tone and motility. L-glutamate (500pmol/30 nL) was microinjected unilaterally into the rostral and caudal areas of the DMV. Data from the first study indicated that neurons labeled with PRV occurred in the DMV, hindbrain raphe nuclei, midbrain Edinger-Westphal nucleus, ventral tegmental area, lateral habenula, and arcuate nucleus. Data from the second study indicated that microinjected L-glutamate into the rostral DMV results in contraction of the pylorus blocked by intravenously administered atropine and ipsilateral vagotomy. L-glutamate injected into the caudal DMV relaxed the pylorus. This response was abolished by ipsilateral vagotomy but not by intravenously administered atropine or L-NG-nitroarginine methyl ester (L-NAME). These findings identify the anatomical and functional brain neurocircuitry involved in controlling the pyloric sphincter. Our results also show that site-specific stimulation of the DMV can differentially influence the activity of the pyloric sphincter by separate vagal nerve pathways.

A biomechanical response of the esophagus participates in swallowing.

Evidence suggests that a biomechanical process participates in esophageal function, but no such function has yet been identified. We investigated the role of a biomechanical process during swallowing in 30 decerebrate cats instrumented using electromyogram (EMG) electrodes, strain gauge force transducers, and manometry. We found that the cervical esophagus has a short-lasting circumferential tension response during the pharyngeal phase of swallowing (CTPP), and a concomitant EMG response. The CTPP magnitude was correlated with magnitudes of contraction of the geniohyoideus, laryngeal elevation force, and esophageal orad elongation force. The magnitude of the CTPP was not correlated with the peak or area under the curve of the concomitant esophageal EMG response. Restricting laryngeal elevation by physical force or transecting the hypoglossal nerves decreased or eliminated the CTPP during swallowing. Elongation of the distal cervical esophagus increased basal circumferential cervical esophageal tension as well as the CTPP. Transecting the vagus or pharyngoesophageal nerves, or administering hexosamine intravenously, had no significant effect on CTPP. We conclude that CTPP is a response to esophageal elongation during laryngeal elevation during the pharyngeal phase of swallowing, which is not caused by muscle contraction or mediated by the nervous system. The CTPP may assist in the distal movement of boluses before activation of the esophageal phase of swallowing, and may serve to prevent esophagopharyngeal reflux. We hypothesize that the CTPP is a biomechanical decrease in elasticity of the circumferential connective tissue of the cervical esophagus caused by the stress of cervical esophageal elongation.NEW & NOTEWORTHY The pharyngeal phase of swallowing includes increased circumferential tension of the cervical esophagus during the pharyngeal phase of swallowing (CTPP). The CTPP is a biomechanical response caused by elongation of the esophagus during laryngeal elevation, and is not caused by muscle contraction or mediated by the nervous system. The CTPP may assist in the distal movement of boluses before activation of the esophageal phase of swallowing, and may serve to prevent esophagopharyngeal reflux.

Investigation of the effect of load rate on creep and hysteresis errors in strain gauge and piezoelectric force transducer

This study includes measurements carried out according to ISO 376 international standard and DKD-R 3-9 guideline by using different low pass filters and continuous data acquisition, with the purpose of comprehensively investigate creep, influence of load rate and influence of load rate on hysteresis in force sensors that have two different measuring principles. It has been revealed and evaluated the contribution of these parameters to the measurement uncertainty.

Enhanced Contractive Tension and Upregulated Muscarinic Receptor 2/3 in Colorectum Contribute to Constipation in 6-Hydroxydopamine-Induced Parkinson's Disease Rats.

Constipation and defecatory dysfunctions are frequent symptoms in patients with Parkinson’s disease (PD). The pathology of Lewy bodies in colonic and rectal cholinergic neurons suggests that cholinergic pathways are involved in colorectal dysmotility in PD. However, the underlying mechanism is unclear. The aim of the present study is to examine the effect of central dopaminergic denervation in rats, induced by injection 6-hydroxydopamine into the bilateral substania nigra (6-OHDA rats), on colorectal contractive activity, content of acetylcholine (ACh), vasoactive intestinal peptide (VIP) and expression of neural nitric oxide synthase (nNOS) and muscarinic receptor (MR). Strain gauge force transducers combined with electrical field stimulation (EFS), gut transit time, immunohistochemistry, ELISA, western blot and ultraperformance liquid chromatography tandem mass spectrometry were used in this study. The 6-OHDA rats exhibited outlet obstruction constipation characterized by prolonged transit time, enhanced contractive tension and fecal retention in colorectum. Pretreatment with tetrodotoxin significantly increased the colorectal motility. EFS-induced cholinergic contractions were diminished in the colorectum. Bethanechol chloride promoted colorectal motility in a dose-dependent manner, and much stronger reactivity of bethanechol chloride was observed in 6-OHDA rats. The ACh, VIP and protein expression of nNOS was decreased, but M2R and M3R were notably upregulated in colorectal muscularis externa. Moreover, the number of cholinergic neurons was reduced in sacral parasympathetic nucleus (SPN) of 6-OHDA rats. In conclusion, central nigrostriatal dopaminergic denervation is associated with decreased cholinergic neurons in SPN, decreased ACh, VIP content, and nNOS expression and upregulated M2R and M3R in colorectum, resulting in colorectal dysmotility, which contributes to outlet obstruction constipation. The study provides new insights into the mechanism of constipation and potential therapeutic targets for constipation in PD patients.

Diurnal changes of colonic motility and regulatory factors for colonic motility in Suncus murinus.

The aim of this study was to investigate the fundamental mechanisms of colonic motility in the house musk suncus (Suncus murinus) as an established animal model of gut motility. To measure gut motility in free-moving conscious suncus, strain gauge force transducers were implanted on the serosa of the colon and gastric body. We recorded diurnal changes in colonic motility and observed the relationship between feeding and colonic motility. Giant migrating contractions (GMCs) of the colon were invariably detected during defecation and tended to increase during the dark period, thereby indicating that colonic motility has a circadian rhythm. Given that GMCs in the suncus were observed immediately after feeding during the dark period, we assume the occurrence of a gastrocolic reflex in suncus, similar to that observed in humans and dogs. We also examined the factors that regulate suncus GMCs. Intravenous administration of 5-HT (100µg/kg), substance P (10 and 100µg/kg), calcitonin gene-related peptide (10µg/kg), and α2 adrenergic receptor antagonist yohimbine (0.5, 1, and 3mg/kg) induced GMC-like contractions, as did intragastric and intracolonic administration of the transient receptor potential vanilloid 1 agonist, capsaicin (1mg/kg). These results indicate that the fundamental mechanisms of colonic motility in suncus are similar to those in humans and dogs, and we thus propose that suncus could serve as a novel small animal model for studying colonic motility.

Linear regression analysis and the GUM: example of temperature influence on force transfer transducers

The deflection of strain-gauge force and torque transducers (the zero-reduced output signal for a given mechanical load) is dependent on the ambient temperature. This is also true of high-precision force transfer transducers used to compare force standard machines. To estimate the extent to which temperature deviations during measurements on different machines affect comparison results and – if necessary – to correct for such deviations, it is important to know the influence of the temperature on the deflection. This effect is usually investigated in special temperature chambers in which the transducer is exposed to various temperatures within a given temperature range while the machine is operated under unchanged laboratory conditions. The regression analysis of the results allows the temperature coefficient to be determined, including an uncertainty analysis. This was done for five force transfer transducers used for a bilateral comparison between NPL (UK) and PTB (Germany).

Calibration of Transducers and of a Coil Compression Spring Constant on the Testing Equipment Simulating the Process of a Pallet Positioning in a Rack Cell

Abstract In a parking house with KOMA TOWER computer-controlled automated parking system it happens that a control system is locked out of service after a pallet has failed to reach the required position during the shifting of pallets, loaded with cars, into rack cells. In this paper is described testing equipment designed by the Institute of Transport, Faculty of Mechanical Engineering, VŠB Technical University of Ostrava for the purpose of simulating the process of pallets shifting into the rack cells in order that the frequency of error messages from the control system during the automated process of cars positioning in rack cells in the parking house may be limited. The paper details two completed parts of the designed testing equipment which provide for the calibration of strain-gauge force transducers and for the detection of coil compressive spring compression in relation to acting pressure force. The description of the third, principal design part will be provided in the next paper, together with the experimentally measured acting forces which generate, in both horizontal and vertical directions, as a pallet brake pulley rolls along a brake haunch length.

Multicriteria approach to design of strain gauge force transducers

Force transducers based on strain gauges are ubiquitous in force measuring equipment. Manufacturers of force transducers have to strive for stronger, cheaper and more accurate force transducers in order to compete successfully on the global market. Transducers have to be designed as fast as possible and require as little experimental work as possible. To that end, a reliable design tool is required. In this paper, we propose a new approach to design of force transducers based on strain gauges. The approach is based on the Parameter Space Investigation method and methods of multicriteria optimization. The transducer’s parameters used as design criteria (output signal at rated load, nonlinearity, etc.) are evaluated using Finite Element Analysis (FEA). The FEA results are used to find the optimal locations of strain gauges. This method was implemented in the software system for multicriteria design of force transducers based on strain gauges. The system was used to design a novel force transducer and can be used for developing new strain gauge-based force transducers and optimizing the existing ones.

Psychophysical effects of an exercise therapy during pediatric stem cell transplantation: a randomized controlled trial.

This study evaluates the physical and psychosocial effects of an inpatient exercise program for children and adolescents undergoing hematopoietic stem cell transplantation (HSCT). Participants (n = 70) were randomized to an exercise intervention (IG: resistance, endurance, and flexibility training) or a non-exercise control group (CG: mental and relaxation training). Pre- (prior hospital admission; T0) and post- (day of discharge; T1) measurements included maximal isometric knee extension strength (KES; strain gauge force transducer), hand grip strength (HGS; JAMAR dynamometer), distance walked in 6 min (6MWD; 6-minute walk test), quality of life (QoL; KINDL-R) and medical parameters. Fifty-seven patients (IG: n = 28; 11.0 (5-17) years; CG: n = 29; 12.0 (6-18) years) completed the study. During hospitalization the IG and CG attended on average 3.1 (2-4) or 2.9 (0.3-4) training sessions weekly. KES, 6MWD, and HGS significantly decreased (p < 0.05) in the CG, while there were no changes in the IG. Pre- to post-changes in 6MWD and HGS differed significantly between groups (p < 0.05). QoL declined in both groups (p < 0.05). Our results indicate that a moderate exercise program is feasible and might counteract a treatment-associated decline of physical performance.

The impact of configuration of the Ilizarov fixator on its stiffness and the degree of loading of distraction rods

BackgroundThe mechanical parameters of the Ilizarov fixator are influenced by many factors related to its spatial configuration. The aim of this study was to experimentally evaluate the impact of the type of implant and the number of distraction rods on the uniformity of loading of distraction rods and stiffness coefficients of the Ilizarov fixator. MethodsThe tests were carried out on a physical model. The model was mounted in a universal loading station MTS 858 Mini Bionix. Forces in distraction rods are measured with the use of strain gauge force transducers. Displacements of bone fragments were measured by means of digital image correction. FindingsIn the case of a fixator with 3 distraction rods, configuration of implants has no statistically significant effect on the forces occurring in distraction rods. In the case of a fixator with 4 distraction rods, there are statistically significant differences in the forces in distraction rods. The highest transverse stiffness coefficients occurs in the system with 4 distraction rods and the configuration of 1K1S implants, while the smallest transverse stiffness coefficients occurs in the fixator with 4 distraction rods and the configuration of 0K1S implants. InterpretationBased on the results of experiments on the physical model, we observed an asymmetry in the distribution of forces transmitted through distraction rods. The configuration with 3 distraction rods provides more uniform distribution of forces in distraction rods and reduces the impact of the implant configuration on transverse stiffness coefficients. The use of a configurations with 4 rods may be advantageous when we want to obtain greater transverse stiffness coefficients of a system consisting of the fixator and fragments of the lengthened bone.

Elobixibat, an ileal bile acid transporter inhibitor, induces giant migrating contractions during natural defecation in conscious dogs.

Chronic constipation affects 14%-17% of the population. Elobixibat, a novel, ileal bile acid transporter (IBAT) inhibitor, has been approved as a new chronic constipation drug in Japan in January 2018. The present study aimed to examine the pharmacological effects of elobixibat on colonic motility in conscious dogs using a telemetry system. Six male beagle dogs were surgically implanted with strain gauge force transducers for gastrointestinal (GI) motility recording. The motility index was calculated from GI motility at each recording site in conscious and nonrestraint dogs. The fasted dogs were orally administered elobixibat (3, 10, or 30mg kg-1 ) or 30mg kg-1 of sennoside as positive control or vehicle using a crossover design and washout period of more than 6days. One hour after drug administration, the dogs were fed chow, and GI motility and defecation were observed for 10hours; GI motility was quantified to calculate giant migrating contractions (GMCs). Fecal bile acids (BAs) were determined as well. Elobixibat and sennoside significantly increased the number of defecations, fecal wet weight, and water content within 10hours after administration. Elobixibat dose-dependently decreased the time to first bowel movement, increased the amount of total fecal BAs, and rapidly induced mild GMCs during defecation; however, higher strength of GMCs was observed with sennoside. Elobixibat induces bowel movements faster than sennoside through a different mechanism. Elobixibat locally inhibits IBAT in the ileal lumen, leading to elevated fecal BAs in the colon and induced mild GMCs during defecation.

Effect of load pad shape on the position error of column type strain gauge force transducer

The position error of column type strain gauge force transducer was analysed, and the effect of load pad on the position error was investigated. Six load pads with various spherical radius were designed and fixed on two column type transducers with capacities of 300 kN and 100 kN to measure their position errors and verify the theory analysis. It is shown that the position error formula could be used to illustrate the effect of load pad shape on the position error. The increment of spherical radius of ball or cup caused the increment of side force and additional moment acted on the force transducer, which resulted in larger position error. The radius should be as small as possible under the permission of material strength.

Effects of Calcitonin Gene-Related Peptide on Colonic Motility and Defecation in Conscious Dogs

BackgroundAlthough intra-arterial infusion of calcitonin gene-related peptide (CGRP) reportedly stimulates giant migrating contractions (GMCs) of the small intestine in conscious dogs, the effect of intravenous CGRP administration on colonic motility remains unclear. In the present study, we investigated the effects of intravenous CGRP on colonic motility and defecation and determined the underlying mechanism of action in conscious dogs. MethodsSixteen Beagle dogs weighing 11–13 kg were included. The effects of intravenous CGRP at doses of 3.33 (with various antagonists), 0.83, and 1.67 μg/kg on colonic motility and defecation were evaluated in neurally intact dogs (n = 6). For comparison, dogs with transection/re-anastomosis (T/R) between the proximal and middle segments of the colon (n = 5) and dogs with extrinsic denervation of the ileocolonic segments (n = 5) also received intravenous CGRP at 3.33 μg/kg. All dogs were equipped with strain gauge force transducers on the ileocolon for measurement of the colonic contractile activity. ResultsIntravenous CGRP evoked GMCs and defecation in the neurally intact group; these stimulatory effects were inhibited by atropine and hexamethonium. Compared with the neurally intact group, the T/R group exhibited similar proximal colonic motility and decreased distal colonic motility after intravenous CGRP administration, whereas the extrinsic denervation group exhibited increased colonic motility overall. ConclusionsIntravenous CGRP induces colonic motility and defecation through acetylcholine release in conscious dogs. The continuity of the enteric nerves plays an important role in CGRP-induced colonic contractions and defecation, while the extrinsic nerves suppress CGRP-induced colonic motility.

Occurrence of the specific long spike burst pattern in the ovine proximal gallbladder as an indication of myoelectric regional variability.

The myoelectrical activity of the ovine gallbladder has not been fully recognised. Five rams were fitted with six small intestinal and three gallbladder electrodes and a strain gauge force transducer was mounted near the gallbladder fundic electrode. In two series of successive experiments, the electromyographical and mechanical recordings were recorded over a period of 5–7 hours. The occurrence of the slow waves in the small bowel was regular, unlike those in the gallbladder. In the gallbladder infundibulum, the specific pattern, called the long spike burst pattern (LSBP), was observed. It comprised usually one or two parts of prolonged duration. The first part resembled the classical (short lasting) spike burst in the small bowel, and its amplitude was lower than that of the second part. The spike burst frequency of the second part was 2–3 times lower than that of the first part. During phase 1-like and phase 2a-like activities, the intensity of the gallbladder LSBP was reduced while enhanced after feeding. In fasted rams, the duration of a specific pattern, observed in the gallbladder infundibulum, was longer than in non-fasted animals and its amplitude was low. Similar events were recorded in the gallbladder corpus, but the specific pattern was shorter and irregular. In the gallbladder fundus, mostly irregular short spike bursts were recorded. It is concluded that in sheep, specific types of the long-lasting groups of spikes occur in the upper gallbladder areas exhibiting myoelectrical regional variability. The character of an LSBP depends on feeding conditions.

Comparing required dislodging forces between different types of posterior palatal seal

Background: In this study forces required to dislodge a maxillary complete denture were compared for different types of posterior palatal seals " Group 1 single beading design , Group 2 double beading design and group 3 with butter fly posterior palatal seal.Materials and Methods :Using a specially designed strain gauge force transducer and strain measuring device ,the force required to dislodge a maxillary complete denture measured and compared. Ten male subjects are selected with age range 55-65 yrs, the primary impression made in the usual manner and the final impression made with zinc oxide euogenol paste after the border seal made with tracing stick impression compound ,then the master cast duplicated using a heavy body silicone impression materials in order to produce a three additional casts, then the casts scraped to incorporate the posterior palatal seals and produce the three groups .a denture base constructed after postdum scraping.Results: Comparing the three groups the results shows that a significant difference found between the group 1 and 2 and group 1 and 3 with no significant difference found between group 2 and 3. Using ANOVA Table with LSD.Conclusion: No Design Provide superior priority than the other type of posterior palatal seals but a double beading and butter fly posterior palatal seal can improve the retention of a maxillary complete denture.

Investigate the effect of three types of denture adhesives on the retention of a poorly fitting maxillary complete denture (Clinical Study)

Background: In this study the forces required to dislodge poorly fitting maxillary complete denture where compared with saliva alone and at different time intervals with the use of three types of denture adhesives, one paste type (Fittydent) and two cream types (Protefix and Incydent).Materials and Methods: Ten subjects with age range between 47-65 years Who wore a maxillary and mandibular complete dentures were selected for this study with their maxillary dentures are lacked sufficient retention(poorly fitting), the dislodgment forces were measured with the aid of a strain gauge force transducer and strain measuring device. The measurements were performed with saliva alone as a control interface medium and at different time intervals (baseline, 1 hour, and 2 hours) after the application of the adhesives.Results: Comparing dislodgement forces using t-test show a highly significant difference (P&lt;0.ooo1) in the amount of retention for all adhesives used at different time intervals in comparison to its values with saliva alone. The Fittydent adhesive paste show a highly significant difference in comparison to Protefix and Incydent adhesives cream at different time intervals.Conclusion: All denture adhesives used were improved the retention of poorly fitting maxillary complete denture but the Fittydent adhesive paste was more effective in increasing the retention than Protefix and Incydent adhesives cream.

The specific long spike burst pattern indicates the presence of regional variability in the ovine gallbladder motor function

AbstractThe myoelectrical activity of ovine gallbladder is incompletely recognized. Accordingly, each of five rams was fitted with six small intestinal and three gallbladder electrodes. The strain gauge force transducer was also mounted near the gallbladder fundic electrode. In two series of chronic experiments the electromyographical and mechanical recordings were conducted during 5–7 h in fasted or non-fasted animals, with or without feeding. The occurrence of the slow waves in the small bowel was common, unlike those in the gallbladder. In the small bowel myoelectrical records both the migrating motility complex and minute rhythm pattern were observed regularly. In the gallbladder, both the migrating motility complex-like activity and the minute rhythm were also denoted in the same time as in the small bowel. In gallbladder infundibulum, and often also in the gallbladder corpus, the specific pattern, called the long spike burst pattern (LSBP) was observed. It comprised usually one or two parts of prolonged duration. The first part resembled the classical (short lasting) spike burst in the small bowel and its amplitude was lower than that of the second part. The spike burst frequency of the second part of the pattern was 2–3 times lower than that of the first part. During phase 1 – and phase 2a-like activity, the frequency of the gallbladder LSBP was reduced in fasted rams. The LSBP amplitude was relatively high and not further enhanced after feeding. In fasted rams, the duration of specific pattern, observed in gallbladder infundibulum, was longer than that in non-fasted animals and its amplitude was low. Similar events were recorded in the gallbladder corpus, but the LSBP was shorter and not regular. In the gallbladder fundus, mostly irregular short spike bursts were recorded. It is concluded that in sheep, specific types of the long-lasting groups of spikes occur in the upper gallbladder areas forming the specific pattern that indicates the presence of the regional variability of the gallbladder motor activity. The character of LSBP depends mostly on feeding conditions.

Study of termination of postprandial gastric contractions in humans, dogs and Suncus murinus: role of motilin- and ghrelin-induced strong contraction.

Stomach contractions show two types of specific patterns in many species, that is migrating motor contraction (MMC) and postprandial contractions (PPCs), in the fasting and fed states respectively. We found gastric PPCs terminated with migrating strong contractions in humans, dogs and suncus. In this study, we reveal the detailed characteristics and physiological implications of these strong contractions of PPC. Human, suncus and canine gastric contractions were recorded with a motility-monitoring ingestible capsule and a strain-gauge force transducer. The response of motilin and ghrelin and its receptor antagonist on the contractions were studied by using free-moving suncus. Strong gastric contractions were observed at the end of a PPC in human, dog and suncus models, and we tentatively designated this contraction to be a postprandial giant contraction (PPGC). In the suncus, the PPGC showed the same property as those of a phase III contraction of MMC (PIII-MMC) in the duration, motility index and response to motilin or ghrelin antagonist administration. Ghrelin antagonist administration in the latter half of the PPC (LH-PPC) attenuated gastric contraction prolonged the duration of occurrence of PPGC, as found in PII-MMC. It is thought that the first half of the PPC changed to PII-MMC and then terminated with PIII-MMC, suggesting that PPC consists of a digestive phase (the first half of the PPC) and a discharge phase (LH-PPC) and that LH-PPC is coincident with MMC. In this study, we propose a new approach for the understanding of postprandial contractions.

Influence of food on the gastric motor effect of the Kampo medicine rikkunshito in rat.

Rikkunshito, one of the Kampo medicines, is widely prescribed as a remedy for various upper gastrointestinal syndromes. The effect of rikkunshito is related to endogenous ghrelin and its active ingredient atractylodin enhances ghrelin receptor signaling. Kampo medicines are traditionally administered before or between meals; however, no definitive benefit of the timing of administration has been proven yet. To clarify the influence of food on the pharmacological action of rikkunshito, we investigated the gastric motor activity and pharmacokinetic profiles of atractylodin after the administration of rikkunshito in fasted and fed rats. Phase III-like contractions in the gastric antrum after an injection of ghrelin were measured using a strain gauge force transducer. Rikkunshito was administered to rats during fasting or after a nutrient test meal. Ghrelin was injected 30minutes later and gastric motility was evaluated. Furthermore, after rikkunshito administration, the pharmacokinetic profiles of atractylodin in the plasma and brain of fasted and free-fed rats were assessed. Rikkunshito administration potentiated ghrelin-induced phase III-like contractions under fasting conditions. This effect was attenuated in animals fed a test meal. Atractylodin was detected pharmacokinetically in the plasma and brain after rikkunshito administration in rats, and free-fed rats exhibited a decreased maximum concentration of plasma atractylodin and a delayed time to reach the maximum concentration. We show that the pharmacological action of rikkunshito is influenced by food in rats. The efficacy of rikkunshito may be associated with decreased absorption of its active ingredient atractylodin when food is in the stomach.