The effect of general anaesthesia on gastric myoelectric activity in experimental pigs

Abstract

BackgroundSurface 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.MethodsFour 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.ResultsThe 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).ConclusionsAll 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.

The pharmacokinetic parameters and the effect of a single and repeated doses of memantine on gastric myoelectric activity in experimental pigs

“…Next dose of 20 mg memantine in the second part induced a prominent drop of the EGG power. In our previous studies, porcine dominant frequency on EGG was fully comparable with the values of healthy humans [13][14][15][16]. We tested different types of anaesthesia previously and found no significant difference [15].…”

“…Our current study brings an important new insight into understanding the effect of memantine on gastric myoelectric activity. We used surface electrogastrography (EGG), a non-invasive method for assessment of gastric myoelectrical activity [9][10][11], which gives comparable results in pigs and in healthy humans, both in dominant frequency and EGG power (areas of amplitudes) [13][14][15][16]. In our current study, single dose of memantine significantly increased DF, while repetitively administrated memantine caused important gastric arrhythmia.…”

“…The second EGG was taken after 7-day intragastric administration (20 mg per day). All EGG recordings were performed under general anaesthesia, using our own method [4,[13][14][15][16]. Briefly, all animals were lying in a right lateral position.…”

Effects of feeding on in vivo motility patterns in the proximal intestine of shorthorn sculpin (Myoxocephalus scorpius)

“…Overall outlines of the exteriorised intestines are displayed below each ST map and each ST map is 20 min long (vertical axis). reduced after the administration of anaesthetic (Ailiani et al, 2009;Torjman et al, 2005), whereas, in pigs, the frequency of slow waves varied depending on the type of anaesthetic used (Tachecí et al, 2013). MS222, the general anaesthetic used in this study, has been shown to impair cardiovascular performance in fish (Hill et al, 2002;Houston et al, 1971).…”

Oesophageal Manometry in Experimental Pigs: Methods and Initial Experience

“…Pigs, as an omnivorous representative, can be used in various preclinical experiments due to their relatively very similar gastrointestinal functions compared to humans (1,2). Our group demonstrated that gastric myoelectrical studies (using electrogastrography) are reliable and feasible in experimental pigs (3)(4)(5)(6)(7). The aim of this current project was to work out our own method of oesophageal manometry in experimental pigs.…”