Ca²⁺ signaling in myenteric interstitial cells of Cajal (ICC-MY) and their role as conditional pacemakers in the colon.

Interstitial cells of Cajal in the plane of the myenteric plexus (ICC-MY) serve as electrical pacemakers in the stomach and small intestine. A similar population of cells is found in the colon, but these cells do not appear to generate regular slow wave potentials, as characteristic in more proximal gut regions. Ca handling mechanisms in ICC-MY of the mouse proximal colon were studied using confocal imaging of muscles from animals expressing GCaMP6f exclusively in ICC.

Integrated responses of the SIP syncytium generate a major motility pattern in the colon.

The peristaltic reflex has been a central concept in gastrointestinal motility; however, evidence was published recently suggesting that post-stimulus responses that follow inhibitory neural responses provide the main propulsive force in colonic motility. This new concept was based on experiments on proximal colon where enteric inhibitory neural inputs are mainly nitrergic. However, the nature of inhibitory neural inputs changes from proximal to distal colon where purinergic inhibitory regulation dominates.

Automated denoising software for calcium imaging signals using deep learning.

Dynamic Ca signaling is crucial for cell survival and death, and Ca imaging approaches are commonly used to study and measure cellular Ca patterns within cells. However, the presence of image noise from instrumentation and experimentation protocols can impede the accurate extraction of Ca signals. Removing noise from Ca Spatio-Temporal Maps (STMaps) is essential for precisely analyzing Ca datasets.

Cells and ionic conductances contributing to spontaneous activity in bladder and urethral smooth muscle.

Smooth muscle organs of the lower urinary tract comprise the bladder detrusor and urethral wall, which have a reciprocal contractile relationship during urine storage and micturition. As the bladder fills with urine, detrusor smooth muscle cells (DSMCs) remain relaxed to accommodate increases in intravesical pressure while urethral smooth muscle cells (USMCs) sustain tone to occlude the urethral orifice, preventing leakage. While neither organ displays coordinated regular contractions as occurs in small intestine, lymphatics or renal pelvis, they do exhibit patterns of rhythmicity at cellular and tissue levels.

Interstitial cell of Cajal-like cells (ICC-LC) exhibit dynamic spontaneous activity but are not functionally innervated in mouse urethra.

Urethral smooth muscle cells (USMC) contract to occlude the internal urethral sphincter during bladder filling. Interstitial cells also exist in urethral smooth muscles and are hypothesized to influence USMC behaviours and neural responses. These cells are similar to Kit interstitial cells of Cajal (ICC), which are gastrointestinal pacemakers and neuroeffectors.

Diversifying laboratory assessment modes broadens engagement with practical competencies in life science students.

Laboratory practicals in life science subjects are traditionally assessed by written reports that reflect disciplinary norms for documenting experimental activities. However, the exclusive application of this assessment has the potential to engage only a narrow range of competencies. In this study, we explored how multiple modes of laboratory assessment might affect student perceptions of learned skills in a life science module.

Ca dynamics in interstitial cells: foundational mechanisms for the motor patterns in the gastrointestinal tract.

The gastrointestinal (GI) tract displays multiple motor patterns that move nutrients and wastes through the body. Smooth muscle cells (SMCs) provide the forces necessary for GI motility, but interstitial cells, electrically coupled to SMCs, tune SMC excitability, transduce inputs from enteric motor neurons, and generate pacemaker activity that underlies major motor patterns, such as peristalsis and segmentation. The interstitial cells regulating SMCs are interstitial cells of Cajal (ICC) and PDGF receptor (PDGFR)α cells.

The TMEM16A blockers benzbromarone and MONNA cause intracellular Ca-release in mouse bronchial smooth muscle cells.

We investigated effects of TMEM16A blockers benzbromarone, MONNA, CaCCA01 and Ani9 on isometric contractions in mouse bronchial rings and on intracellular calcium in isolated bronchial myocytes. Separate concentrations of carbachol (0.1-10 μM) were applied for 10 min periods to bronchial rings, producing concentration-dependent contractions that were well maintained throughout each application period.

Ca Signaling Is the Basis for Pacemaker Activity and Neurotransduction in Interstitial Cells of the GI Tract.

Years ago gastrointestinal motility was thought to be due to interactions between enteric nerves and smooth muscle cells (SMCs) in the tunica muscularis. Thus, regulatory mechanisms controlling motility were either myogenic or neurogenic. Now we know that populations of interstitial cells, c-Kit (interstitial cells of Cajal or ICC), and PDGFRα cells (formerly "fibroblast-like" cells) are electrically coupled to SMCs, forming the SIP syncytium.

Ca -activated Cl channels (TMEM16A) underlie spontaneous electrical activity in isolated mouse corpus cavernosum smooth muscle cells.

Penile detumescence is maintained by tonic contraction of corpus cavernosum smooth muscle cells (CCSMC), but the underlying mechanisms have not been fully elucidated. The purpose of this study was to characterize the mechanisms underlying activation of TMEM16A Ca -activated Cl channels in freshly isolated murine CCSMC. Male C57BL/6 mice aged 10-18 weeks were euthanized via intraperitoneal injection of sodium pentobarbital (100 mg.

Propagation of Pacemaker Activity and Peristaltic Contractions in the Mouse Renal Pelvis Rely on Ca-activated Cl Channels and T-Type Ca Channels.

The process of urine removal from the kidney occurs via the renal pelvis (RP). The RP demarcates the beginning of the upper urinary tract and is endowed with smooth muscle cells. Along the RP, organized contraction of smooth muscle cells generates the force required to move urine boluses toward the ureters and bladder.

Calcium transients in intramuscular interstitial cells of Cajal of the murine gastric fundus and their regulation by neuroeffector transmission.

Enteric neurotransmission is critical for coordinating motility throughout the gastrointestinal (GI) tract. However, there is considerable controversy regarding the cells that are responsible for the transduction of these neural inputs. In the present study, utilization of a cell-specific calcium biosensor GCaMP6f, the spontaneous activity and neuroeffector responses of intramuscular ICC (ICC-IM) to motor neural inputs was examined.

Insights on gastrointestinal motility through the use of optogenetic sensors and actuators.

The muscularis of the gastrointestinal (GI) tract consists of smooth muscle cells (SMCs) and various populations of interstitial cells of Cajal (ICC), platelet-derived growth factor receptor α (PDGFRα ) cells, as well as excitatory and inhibitory enteric motor nerves. SMCs, ICC and PDGFRα cells form an electrically coupled syncytium, which together with inputs from the enteric nervous system (ENS) regulates GI motility. Early studies evaluating Ca signalling behaviours in the GI tract relied upon indiscriminate loading of tissues with Ca dyes.

Propulsive colonic contractions are mediated by inhibition-driven poststimulus responses that originate in interstitial cells of Cajal.

The peristaltic reflex is a fundamental behavior of the gastrointestinal (GI) tract in which mucosal stimulation activates propulsive contractions. The reflex occurs by stimulation of intrinsic primary afferent neurons with cell bodies in the myenteric plexus and projections to the lamina propria, distribution of information by interneurons, and activation of muscle motor neurons. The current concept is that excitatory cholinergic motor neurons are activated proximal to and inhibitory neurons are activated distal to the stimulus site.

Ca signalling in interstitial cells of Cajal contributes to generation and maintenance of tone in mouse and monkey lower oesophageal sphincters.

The lower oesophageal sphincter (LES) generates tone and prevents reflux of gastric contents. LES smooth muscle cells (SMCs) are relatively depolarised, facilitating activation of Ca 1.2 channels to sustain contractile tone.

Isolating and Imaging Live, Intact Pacemaker Regions of Mouse Renal Pelvis by Vibratome Sectioning.

The renal pelvis (RP) is a funnel-shaped, smooth muscle structure that facilitates normal urine transport from the kidney to the ureter by regular, propulsive contractions. Regular RP contractions rely on pacemaker activity, which originates from the most proximal region of the RP at the pelvis-kidney junction (PKJ). Due to the difficulty in accessing and preserving intact preparations of the PKJ, most investigations on RP pacemaking have focused on single-cell electrophysiology and Ca imaging experiments.

Role of Ano1 Ca-activated Cl channels in generating urethral tone.

Urinary continence is maintained in the lower urinary tract by the contracture of urethral sphincters, including smooth muscle of the internal urethral sphincter. These contractions occlude the urethral lumen, preventing urine leakage from the bladder to the exterior. Over the past 20 years, research on the ionic conductances that contribute to urethral smooth muscle contractility has greatly accelerated.

Ca signaling driving pacemaker activity in submucosal interstitial cells of Cajal in the murine colon.

Interstitial cells of Cajal (ICC) generate pacemaker activity responsible for phasic contractions in colonic segmentation and peristalsis. ICC along the submucosal border (ICC-SM) contribute to mixing and more complex patterns of colonic motility. We show the complex patterns of Ca signaling in ICC-SM and the relationship between ICC-SM Ca transients and activation of smooth muscle cells (SMCs) using optogenetic tools.

The intracellular Ca release channel TRPML1 regulates lower urinary tract smooth muscle contractility.

TRPML1 (transient receptor potential mucolipin 1) is a Ca-permeable, nonselective cation channel that is predominantly localized to the membranes of late endosomes and lysosomes (LELs). Intracellular release of Ca through TRPML1 is thought to be pivotal for maintenance of intravesicular acidic pH as well as the maturation, fusion, and trafficking of LELs. Interestingly, genetic ablation of TRPML1 in mice ( ) induces a hyperdistended/hypertrophic bladder phenotype.

A high throughput machine-learning driven analysis of Ca spatio-temporal maps.

High-resolution Ca imaging to study cellular Ca behaviors has led to the creation of large datasets with a profound need for standardized and accurate analysis. To analyze these datasets, spatio-temporal maps (STMaps) that allow for 2D visualization of Ca signals as a function of time and space are often used. Methods of STMap analysis rely on a highly arduous process of user defined segmentation and event-based data retrieval.

A novel intramuscular Interstitial Cell of Cajal is a candidate for generating pacemaker activity in the mouse internal anal sphincter.

The internal anal sphincter (IAS) generates phasic contractions and tone. Slow waves (SWs) produced by interstitial cells of Cajal (ICC) underlie phasic contractions in other gastrointestinal regions. SWs are also present in the IAS where only intramuscular ICC (ICC-IM) are found, however the evidence linking ICC-IM to SWs is limited.

TRPML1 channels initiate Ca sparks in vascular smooth muscle cells.

TRPML1 (transient receptor potential mucolipin 1) is a Ca-permeable, nonselective cation channel localized to the membranes of endosomes and lysosomes and is not present or functional on the plasma membrane. Ca released from endosomes and lysosomes into the cytosol through TRPML1 channels is vital for trafficking, acidification, and other basic functions of these organelles. Here, we investigated the function of TRPML1 channels in fully differentiated contractile vascular smooth muscle cells (SMCs).

Excitatory cholinergic responses in mouse colon intramuscular interstitial cells of Cajal are due to enhanced Ca release via M receptor activation.

Colonic intramuscular interstitial cells of Cajal (ICC-IM) are associated with cholinergic varicosities, suggesting a role in mediating excitatory neurotransmission. Ca release in ICC-IM activates Ano1, a Ca -activated Cl conductance, causing tissue depolarization and increased smooth muscle excitability. We employed Ca imaging of colonic ICC-IM in situ, using mice expressing GCaMP6f in ICC to evaluate ICC-IM responses to excitatory neurotransmission.

Identification and classification of interstitial cells in the mouse renal pelvis.

Key Points: Platelet-derived growth factor receptor-α (PDGFRα) is a novel biomarker along with smooth myosin heavy chain for the pacemaker cells (previously termed 'atypical' smooth muscle cells) in the murine and cynomolgus monkey pelvis-kidney junction. PDGFRα cells present in adventitial and urothelial layers of murine renal pelvis do not express smooth muscle myosin heavy chain (smMHC) but are in close apposition to nerve fibres. Most c-Kit cells in the renal pelvis are mast cells.