Mapping slow waves and spikes in chronically instrumented conscious dogs: implantation techniques and recordings
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Myoelectric recordings from the intestines in conscious animals have been limited to a few electrode sites with relatively large inter-electrode distances. The aim of this project was to increase the number of recording sites to allow high-resolution reconstruction of the propagation of myoelectrical signals. Sets of six unipolar electrodes, positioned in a 3×2 array, were constructed. A silver ring close to each set served as the reference electrodes. Inter-electrode distances varied from 4 to 8 mm. Electrode sets, to a maximum of 4, were implanted in various configurations allowing recording from 24 sites simultaneously. Four sets of 6 electrodes each were implanted successfully in 11 female Beagles. Implantation sites evaluated were the upper small intestine (n=10), the lower small intestine (n=4) and the stomach (n=3). The implants remained functional for 7.2 months (median; range 1.4–27.3 months). Recorded signals showed slow waves at regular intervals and spike potentials. In addition, when the sets were positioned close together, it was possible to re-construct the propagation of individual slow waves, to determine their direction of propagation and to calculate their propagation velocity. No signs or symptoms of interference with normal GI-function were observed in the tested animals. With this approach, it is possible to implant 24 extracellular electrodes on the serosal surface of the intestines without interfering with its normal physiology. This approach makes it possible to study the electrical activities of the GI system at high resolution in vivo in the conscious animal.
KeywordsElectrical mapping Conscious animal Gastrointestinal system
The authors wish to acknowledge the expert animal care provided by the staff of the Department of Laboratory Animal Science, in particular Mr Jef Ceulemans for training the dogs and Mr Piet Dierckx, DVM and Mrs Leen Roefs for daily animal care. Dr Luc Andries (Histogenex NV, Edegem, Belgium) provided the histology images.
- 7.Lammers WJ, Ver Donck L, Schuurkes JA (2003) Stephen B. longitudinal and circumferential spike patches in the canine small intestine in vivo. Am J Physiol 285:G1014–G1027Google Scholar
- 8.Lammers WJEP, Stephen B, Arafat K, Manefield GW (1996) High resolution mapping in the gastrointestinal system: initial results. Neurogastroenterol Mot 8:207–216Google Scholar
- 10.Lammers WJEP (2000) Propagation of individual spikes as ‘patches’ of activation in the isolated feline duodenum. Am J Physiol 278:G297–G307Google Scholar