Contraction of gut smooth muscle cells assessed by fluorescence imaging

Abstract

Here we discuss the development of a novel cell imaging system for the evaluation of smooth muscle cell (SMC) contraction. SMCs were isolated from the circular and longitudinal muscular layers of mouse small intestine by enzymatic digestion. SMCs were stimulated by test agents, thereafter fixed in acrolein. Actin in fixed SMCs was stained with phalloidin and cell length was determined by measuring diameter at the large end of phalloidin-stained strings within the cells. The contractile response was taken as the decrease in the average length of a population of stimulated-SMCs. Various mediators and chemically identified compounds of daikenchuto (DKT), pharmaceutical-grade traditional Japanese prokinetics, were examined. Verification of the integrity of SMC morphology by phalloidin and DAPI staining and semi-automatic measurement of cell length using an imaging analyzer was a reliable method by which to quantify the contractile response. Serotonin, substance P, prostaglandin E2 and histamine induced SMC contraction in concentration-dependent manner. Two components of DKT, hydroxy-α-sanshool and hydroxy-β-sanshool, induced contraction of SMCs. We established a novel cell imaging technique to evaluate SMC contractility. This method may facilitate investigation into SMC activity and its role in gastrointestinal motility, and may assist in the discovery of new prokinetic agents.

Immunolocalization of glutaryl-CoA dehydrogenase (GCDH) in adult and embryonic rat brain and peripheral tissues

“…Tryptophan is a precursor of serotonin, known to act as neurotransmitter in the gut. A recent study has shown that smooth muscle cells contract under the influence of serotonin in a dose-dependent manner (Tokita et al, 2015). From the administration of serotonin as an antidepressive drug we know that high serotonin levels lead to nausea, loss of appetite, anorexia, vomiting and diarrhea; symptoms comparable to what is observed in GA-I patients.…”

Mammary mechanobiology: mechanically-activated ion channels in lactation and involution

“…Quantitative assessment of cell morphology before and after oxytocin stimulation revealed a 32.1 ± 0.8% (P < 0.05) decrease in surface area during basal cell contraction (Fig. 1B), making these epithelial cell contractions comparable in magnitude to those of cardiomyocytes and intestinal smooth muscle cells (32,33).…”

“…(60). All samples were obtained with informed consent and patients (female, aged[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] were recruited under a protocol approved by the Indiana University Institutional Review Board (IRB protocol number 1011003097) and according to The Code of Ethics of the World Medical Association (Declaration of Helsinki). The current project received additional, site-specific approval from the Mater Misericordiae Ltd Human Research Ethics Committee.…”

Hypertension-linked mechanical changes of rat gut

“…Our group has found extensive evidence of gut dysbiosis in both the Spontaneously Hypertensive Rat (SHR) model and in patients with high blood pressure [2]. Since cardiovascular tissue stiffens in response to smooth muscle remodeling in HTN [1,4], and recognizing gastrointestinal (GI) tissue comprises smooth muscle cells to move waste and facilitate digestion [5], we hypothesized that the gut similarly will stiffen with HTN through increased matrix deposition and smooth muscle cell proliferation. Vascular smooth muscle remodeling has already been demonstrated in the SHR line [6], making this rat line a good model to investigate gastrointestinal smooth muscle remodeling as a result of gut dysbiosis and HTN.…”