Enteric neuronal substrates underlying spontaneous and evoked neurogenic contractions in mouse colon.

Background And Aims: Gastrointestinal motility persists when peripheral cholinergic signaling is blocked genetically or pharmacologically, and a recent study suggests nitric oxide drives propagating neurogenic contractions.

Methods: To determine the neuronal substrates that underlie these contractions, we measured contractile-associated movements together with calcium responses of cholinergic or nitrergic myenteric neurons in un-paralyzed ex vivo preparations of whole mouse colon. We chose to look at these two subpopulations because they encompass nearly all myenteric neurons.

Immunohistochemical characterization of interstitial cells and their spatial relationship to motor neurons within the mouse esophagus.

Interstitial cells of Cajal (ICC) and PDGFRα cells regulate smooth muscle motility in the gastrointestinal (GI) tract, yet their function in the esophagus remains unknown. The mouse esophagus has been described as primarily skeletal muscle; however, ICC  have been identified in this region. This study characterizes the distribution of skeletal and smooth muscle cells (SMCs) and their spatial relationship to ICC, PDGFRα cells, and intramuscular motor neurons in the mouse esophagus.

Immunohistochemical characterization of interstitial cells and their relationship to motor neurons within the mouse esophagus.

Interstitial cells of Cajal (ICC) and PDGFRα cells regulate smooth muscle motility in the gastrointestinal (GI) tract. However, their role(s) in esophageal motility are still unclear. The mouse esophagus has traditionally been described as almost entirely skeletal muscle in nature though ICC have been identified along its entire length.

Modulation of intracellular calcium activity in interstitial cells of Cajal by inhibitory neural pathways within the internal anal sphincter.

The internal anal sphincter (IAS) functions to maintain continence. Previous studies utilizing mice with cell-specific expression of GCaMP6f revealed two distinct subtypes of intramuscular interstitial cells of Cajal (ICC-IM) with differing Ca activities in the IAS. The present study further examined Ca activity in ICC-IM and its modulation by inhibitory neurotransmission.

Rhythmic calcium transients in smooth muscle cells of the mouse internal anal sphincter.

Background: The internal anal sphincter (IAS) exhibits slow waves (SWs) and tone that are dependent upon L-type Ca channels (Cav ) suggesting that phasic events (ie, SWs) play a fundamental role in tone generation. The present study further examined phasic activity in the IAS by measuring the spatiotemporal properties of Ca transients (CTs) in IAS smooth muscle cells (SMCs).

Methods: Ca transients were recorded with spinning disk confocal microscopy from the IAS of SM-GCaMP mice.