Relationship Between Intestinal Slow-waves, Spike-bursts, and Motility, as Defined Through High-resolution Electrical and Video Mapping

Abstract

Background/AimsHigh-resolution extracellular mapping has improved our understanding of bioelectric slow-wave and spike-burst activity in the small intestine. The spatiotemporal correlation of electrophysiology and motility patterns is of critical interest to intestinal function but remains incompletely defined. MethodsIntestinal jejunum segments from in vivo pigs and rabbits were exteriorized, and simultaneous high-resolution extracellular recordings and video recordings were performed. Contractions were quantified with strain fields, and the frequencies and velocities of motility patterns were calculated. The amplitudes, frequencies, and velocities of slow-wave propagation patterns and spike-bursts were quantified and visualized. In addition, the duration, size and energy of spike-burst patches were quantified. ResultsSlow-wave associated spike-bursts activated periodically at 10.8 ± 4.0 cycles per minute (cpm) in pigs and 10.2 ± 3.2 cpm in rabbits, while independent spike-bursts activated at a frequency of 3.2 ± 1.8 cpm. Independent spike-bursts had higher amplitude and longer duration than slow-wave associated spike-bursts (1.4 ± 0.8 mV vs 0.1 ± 0.1 mV, P < 0.001; 1.8 ± 1.4 seconds vs 0.8 ± 0.3 seconds, P < 0.001 in pigs). Spike-bursts that activated as longitudinal or circumferential patches were associated with contractions in the respective directions. Spontaneous peristaltic contractions were elicited by independent spike-bursts and travelled slower than slow-wave velocity (3.7 ± 0.5 mm/sec vs 10.1 ± 4.7 mm/sec, P = 0.007). Cyclic peristaltic contractions were driven by slow-wave associated spike-bursts and were coupled to slow-wave velocity and frequency in rabbit (14.2 ± 2.3 mm/sec vs 11.5 ± 4.6 mm/sec, P = 0.162; 11.0 ± 0.6 cpm vs 10.8 ± 0.6 cpm, P = 0.970). ConclusionsMotility patterns were dictated by patterns of spike-burst patches. When spike-bursts were coupled to slow-waves, periodic motility patterns were observed, while when spike-bursts were not coupled to slow-waves, spontaneous aperiodic motility patterns were captured.

High-Energy Pacing in the Jejunum Elicits Pulsatile Segmental Contractions

“…A key limitation of this framework is the manual tracing of the active intestinal segment to compute strain, which could introduce observer bias. Automated methods that quantify regional deformations using strain fields can be adopted in future to mitigate this effect [29], [45]. Furthermore, pendular contractions were observed occasionally at higher pulse-amplitudes (6 and 8 mA), but the analysis was restricted to segmental contractions as pendular contractions occurred sporadically only in 10 % of the higher pacing energy studies.…”