Electrical slow wave activity of the cat stomach: its frequency gradient and the effect of indomethacin

Abstract

The present study was performed to establish the intrinsic frequency of the slow waves in different regions of the cat stomach, to define the propagation velocity of the slow wave along the stomach, and to determine whether endogenous prostaglandins can affect the slow wave frequency. In 20 cats, electrical activity was recorded from the anterior wall of the intact stomach in vivo and in vitro, and in vitro after cutting the stomach into 16 pieces to isolate each pair of electrodes. In vivo, slow waves (4.1 +/- 0.5 cpm) were seen only from mid corpus to pylorus, the apparent propagation velocity decreasing towards the antrum. In vitro: (a) after cutting, the slow wave frequency increased, to a maximum in 1 h (12 +/- 1.8 cpm; range 10.2-17.3), with the highest frequency always in the mid or orad corpus, usually on the greater curvature (GC), (b) with indomethacin (10(-5) M) the increase in slow wave frequency was prevented or reversed, and there was a frequency gradient with the highest frequency (4.4 +/- 1.2 cpm) uniformly located in the most proximal active site on the GC, and (c) slow waves on the GC were more stable, regular and continuous than on the lesser curvature (LC), the difference being most evident in the corpus. The results suggest that the cat stomach behaves as a system of electrically coupled oscillators of different frequencies. The dominant oscillator of highest frequency is situated in the proximal corpus of the GC, with the remainder of the distal stomach entrained at this frequency. All gastric slow wave oscillators can be driven to higher frequencies by endogenous prostaglandins. The decreasing velocity of slow wave propagation distally suggests that oscillator properties and/or coupling among oscillators differs in the cat.

Circumferential and functional re‐entry of in vivo slow‐wave activity in the porcine small intestine

“…Previously, it has generally been assumed that in vivo intestinal slow‐wave frequencies and propagation patterns are governed solely by the intrinsic frequencies of ICC, influenced by the variable coupling between adjacent segments . The enteric nervous system and intrinsic agents, such as prostaglandins, are also known to influence slow‐wave frequencies . Our study showed that in vivo intestinal slow‐wave frequency can also be governed by re‐entrant foci, in which frequencies of ICC are entrained according to relationships of velocity, wavelength, and organ geometry, as seen in Fig.…”

Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

“…Particularly, external electrical stimulations could also be studied, as stretch-induced contractions, blocking the neural activity to better identify the role of ICCs in modulating the contractile response to cooling. Moreover, in vitro tissue studies have demonstrated that some inflammatory mediators, especially prostaglandins, can modulate the frequency of contractions in the stomach (50,73); for this reason, use of selective inhibitors would help to better explore the mechanism responsible for the cooling contractile response of smooth muscle tissue. An extended data set for a wider range of thermal conditions would also help to unveil the contractile response of longitudinal-and circular-oriented human colonic strips.…”

The impact of surgical excisions on human gastric slow wave conduction, defined by high‐resolution electrical mapping and in silico modeling

“…; Video S5), which could further complicate postoperative gastric recovery in susceptible patients. Aberrant slow wave initiation following tissue manipulation could be due to several influences, including the release of prostaglandins, which are known to have a chronotropic effect on ICC …”