BACKGROUND: Surface electrogastrography (EGG) is a non-invasive method for clinical assessment of gastric myoelectrical activity. Different forms of general anaesthesia might have various effects on porcine EGG. The aim of this study was to evaluate the impact of different anaesthetic agents on EGG in experimental pigs. METHODS: Four 15-minute EGG intervals were recorded and analysed. A baseline EGG recording was started 20 minutes after intramuscular injection of ketamine and azaperone (periods A and B). Four different regimens of general anaesthesia followed immediately after the baseline EGG (5 pigs in each experimental group): thiopental, isoflurane, nitrous oxide and isoflurane plus nitrous oxide. EGG recordings followed for the next 30 minutes under general anaesthesia (periods C and D). The dominant frequencies of slow waves were compared between the baseline intervals A and B and periods C and D under general anaesthesia. RESULTS: The mean dominant frequency was within the normal range (2.3 - 3.5 cycles per minute) in all animals in all regimens. Thiopental general anaesthesia did not influence any change of the dominant frequency of slow waves. Nitrous oxide general anaesthesia increased the dominant frequency of slow waves in a statistically significant manner (baseline: 2.93 ± 0.53 and 3.01 ± 0.53; under general anaesthesia: 3.25 ± 0.34 and 3.29 ± 0.38 cycles per minute; p < 0.001, p = 0.003, p < 0.001, p < 0.001). Nitrous oxide together with isoflurane induced a statistically significant decrease of dominant frequency in the last 15-minute interval (2.66 ± 0.55 cycles per minute) compared to the baseline recording (2.81 ± 0.49; p = 0.030). CONCLUSIONS: All changes of porcine gastric myoelectric activity assessed by the dominant frequency of slow waves during EGG remained within the normal range although some of them achieved statistical significance. Thus all tested agents used for general anaesthesia can be recommended in preclinical studies with porcine models focused on gastric myoelectric activity without any risk of compromising the results. Thiopental seems to be the most suitable as it did not cause any changes at all.

• MeSH
• anestetika celková farmakologie   MeSH
• isofluran farmakologie   MeSH
• migrující myoelektrický komplex účinky léků   fyziologie   MeSH
• modely u zvířat MeSH
• oxid dusný farmakologie   MeSH
• prasata MeSH
• thiopental farmakologie   MeSH
• žaludek účinky léků   patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Úvod: Téměř všechny preklinické studie u experimentálních prasat je třeba provádět v celkové anestezii. Ketamin je běžně používán jako úvod do anestezie. Avšak dosud nezodpovězenou otázkou je, zda ketamin, antagonista NMDA-receptorů, ovlivňuje motorické funkce žaludku. Cílem této práce bylo vyšetřit žaludeční myoelektrickou aktivitu prasete metodou elektrogastrografie (EGG). Metody: Do studie bylo zařazeno 17 samic Sus scrofa f. domestica (průměrná hmotnost 36,2 ± 3,8 kg). Pro úvod do anestezie byla použita různá léčiva: skupina A (n = 5): medetomidin 0,1 mg/kg i. m.; butorfanol 0,3 mg/kg i. m.; midazolam 0,3 mg/kg i. m.; skupina B (n = 6): azaperon 2,2 mg/kg i. m.; skupina C (n = 6): ketamin 20 mg/kg i. m.; azaperon 2,2 mg/kg i. m. Celková anestezie ve všech skupinách pokračovala podáváním 1% propofolu (opakované 1ml bolusy, celkem 10–12 ml i.v.). Záznam EGG začal za 15 min. po úvodu do anestezie a trval 30 min. Výsledky byly vyhodnoceny jako dominantní frekvence pomalých žaludečních vln (DF) a plochy pod křivkou (EGG power). Výsledky: Celkem bylo vyhodnoceno 510 jednominutových EGG intervalů (každý dvakrát: DF a power). DF byly (průměr ± směrodatná odchylka): 1,4 ± 0,4 (skupina A), 1,3 ± 0,3 (skupina B) a 0,2 ± 0,1 cykly/min. (skupina C). Rozdíly mezi skupinou C a skupinami A a B byly statisticky významné (p < 0,001). Mediány ploch pod křivkou (IQR) byly: 0,13 (0,02–0,44; skupina A); 0,13 (0,03–0,54; skupina B) a 0,30 V2 (0,07–1,44; skupina C). Rozdíl mezi skupinami A a C byl na hranici statistické významnosti (p = 0,066; chyba 2. typu beta 0,295). Závěry: Ketamin, a to i v jedné intramuskulární dávce, ovlivňuje myoelektrické funkce žaludku prasete. Proto by neměl být používán v preklinických studiích gastrointestinální motility experimentálních prasat.

Introduction: Preclinical studies in experimental pigs are carried out mostly under general anaesthesia. Ketamine is commonly used for induction of anaesthesia. However, there are concerns that ketamine, an NMDA-receptor antagonist, may influence gastric motor function. The aim of this study was to investigate porcine gastric myoelectric activity by means of electrogastrography (EGG). Methods: Seventeen female animals (mean weight 36.2±3.8 kg) were enrolled. Drugs used for induction of anaesthesia were: Group A (n=5): medetomidine 0.1 mg/kg i. m.; butorphanol 0.3 mg/kg i. m.; midazolam 0.3 mg/kg i. m.; Group B (n=6): azaperon 2.2 mg/kg i. m.; Group C (n=6): ketamine 20 mg/kg i. m.; azaperon 2.2 mg/kg i. m., followed in all groups by i.v. 1% propofol (repeated one-mL boluses, 10–12 mL in total). EGG recording started 15 min. after the induction administration and lasted 30 min. Results were evaluated as the dominant frequency of gastric slow waves (DF) and EGG power (areas of amplitudes). Results: In total, 510 one-minute EGG intervals were assessed. DFs were (mean ± standard deviation): 1.4±0.4 (Group A), 1.3±0.3 (Group B) and 0.2±0.1 cycles per min. (Group C). The differences between group C and groups A and B were statistically significant (p<0.001). Median power (IQR) was 0.13 (0.02–0.44; Group A), 0.13 (0.03–0.54; Group B) and 0.30 V2 (0.07–1.44; Group C). The difference between groups A and C was of borderline significance (p=0.066; type 2 error beta 0.295). Conclusions: Ketamine, administered even in a single intramuscular dose, affected myoelectric function of the porcine stomach. Therefore, it should be avoided in gastrointestinal motility studies in experimental pigs.

• MeSH
• elektromyografie metody   MeSH
• gastrointestinální motilita * účinky léků   MeSH
• ketamin * MeSH
• modely nemocí na zvířatech MeSH
• prasata MeSH
• receptory N-methyl-D-aspartátu * účinky léků   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

BACKGROUND: Memantine, currently available for the treatment of Alzheimer's disease, is an uncompetitive antagonist of the N-methyl-D-aspartate type of glutamate receptors. Under normal physiologic conditions, these unstimulated receptor ion channels are blocked by magnesium ions, which are displaced after agonist-induced depolarization. In humans, memantine administration is associated with different gastrointestinal dysmotility side effects (vomiting, diarrhoea, constipation, motor-mediated abdominal pain), thus limiting its clinical use. Mechanism of these motility disorders has not been clarified yet. Pigs can be used in various preclinical experiments due to their relatively very similar gastrointestinal functions compared to humans. The aim of this study was to evaluate the impact of a single and repeated doses of memantine on porcine gastric myoelectric activity evaluated by means of electrogastrography (EGG). METHODS: Six adult female experimental pigs (Sus scrofa f. domestica, mean weight 41.7±5.0 kg) entered the study for two times. The first EGG was recorded after a single intragastric dose of memantine (20 mg). In the second part, EGG was accomplished after 7-day intragastric administration (20 mg per day). All EGG recordings were performed under general anaesthesia. Basal (15 minutes) and study recordings (120 minutes) were accomplished using an EGG stand (MMS, Enschede, the Netherlands). Running spectral analysis based on Fourier transform was used. Results were expressed as dominant frequency of gastric slow waves (DF) and power analysis (areas of amplitudes). RESULTS: Single dose of memantine significantly increased DF, from basic values (1.65±1.05 cycles per min.) to 2.86 cpm after 30 min. (p = 0.008), lasting till 75 min. (p = 0.014). Basal power (median 452; inter-quartile range 280-1312 μV^2) raised after 15 min. (median 827; IQR 224-2769; p = 0.386; NS), lasting next 30 min. Repetitively administrated memantine caused important gastric arrhythmia. Basal DF after single and repeated administration was not different, however, a DF increase in the second part was more prominent (up to 3.18±2.16 after 15 and 30 min., p<0.001). In comparison with a single dose, basal power was significantly higher after repetitively administrated memantine (median 3940; IQR 695-15023 μV^2; p<0.001). Next dose of 20 mg memantine in the second part induced a prominent drop of power after 15 min. (median 541; IQR 328-2280 μV^2; p<0.001), lasting till 120 min. (p<0.001). CONCLUSIONS: Both single and repeated doses of memantine increased DF. Severe gastric arrhythmia and long-lasting low power after repeated administration might explain possible gastric dysmotility side effects in the chronic use of memantine.

• MeSH
• Alzheimerova nemoc farmakoterapie   MeSH
• antagonisté excitačních aminokyselin aplikace a dávkování   škodlivé účinky   MeSH
• aplikace orální MeSH
• elektromyografie MeSH
• gastrointestinální motilita účinky léků   fyziologie   MeSH
• gastrointestinální nemoci chemicky indukované   diagnóza   patofyziologie   MeSH
• lidé MeSH
• memantin aplikace a dávkování   škodlivé účinky   MeSH
• modely nemocí na zvířatech MeSH
• Sus scrofa MeSH
• žaludek účinky léků   patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH