Regional differences of the effects of acetylcholine in the human gastric circular muscle

Abstract

The motor functions of the stomach have traditionally been regarded to have regional differences. However, to date there have been only a few data investigating whether such regional differences in motor function exist in the human stomach. The aims of the present study were to examine the spontaneous activity and responses to acetylcholine in the anatomically defined regions of human stomach. Human gastric circular muscle tissues from fundus, corpus, and antrum were obtained from 25 patients (14 men, 11 women with a mean age of 55.2 yr; 36-74 yr) undergoing gastrectomy for gastric cancers. Isometric force measurements were performed by using muscle strips from the different regions of the human stomach under basal conditions and in response to the exogenous application of acetylcholine. Spontaneous phasic contractions were observed in all human gastric smooth muscles. However, the responses to acetylcholine displayed regional differences. In the gastric antrum, there was a dose-dependent increase in the peak contraction, contractile frequency, and amplitude of contraction after acetylcholine exposure (up to 1 μM). However, there was no significant change in the basal tone. In the corpus and fundus, acetylcholine induced a dose-dependent increase in the peak contraction and basal tone. However, there was no significant change in the contractile frequency or amplitude of contraction. In conclusion, the response of human gastric circular muscle to acetylcholine displayed regional differences between the antrum and the corpus and fundus. This finding suggested the presence of distinct functional regions in human stomach.

SMB myosin heavy chain knockout enhances tonic contraction and reduces the rate of force generation in ileum and stomach antrum

“…Thus it may be that the SMA MHC is required for enhanced tonic force, but this only occurs when the proper regulatory pathways are also invoked to bring about this maintained force generation. In addition, it has been reported that CCh activation results in spontaneous contraction of gastrointestinal smooth muscle (52,62), and our force trace data show spontaneous contractions caused by CCh (Fig. 7).…”

“…Unlike KPSS stimulation, CCh activation includes spontaneous contractions of gastrointestinal smooth muscle as shown in Fig. 7 (14,52,62), which may confound the area under the curve measurement. To test this, the spontaneous contractions induced by CCh were compared between SMB (ϩ/ϩ) and SMB (Ϫ/Ϫ) by comparing spike number and average amplitude from the time of peak force to 10 min after.…”

Nitrergic Pathway Is the Main Contributing Mechanism in the Human Gastric Fundus Relaxation: An In Vitro Study

“…These experiments were conducted using standard organ bath techniques, as previously described in another study by our laboratory [26,27]. …”

The effect of levosulpiride on in vitro motor patterns in the human gastric fundus, antrum, and jejunum

“…Most of the studies to characterize the contractility patterns and neuro‐muscular transmission in the stomach in vitro have been performed on animal models . Only few studies have described neuro‐muscular transmission in the stomach and even fewer, in vitro contractility patterns . However, it has been pointed out that the frequencies estimated for spontaneous rhythmic contractions in the stomach of about 2–4 cycles per minute (cpm) based on animal models and electrogastrography might be underestimated in these contractility studies, and the standards for clinical evaluation might have to be reconsidered .…”