Interstitial cell of Cajal

Interstitial cells of Cajal (ICC) are

The picture to the right shows an isolated Interstitial cell of Cajal from the Myenteric plexus of the mouse small intestine grown in a primary cell culture. This cell type can be characterized morphologically as having a small cell body often triangular or stellate-shaped with several long processes branching out into secondary and tertiary extensions - these processes often contact smooth muscle cells. They have contractile behaviour in both the cell body and the extended processes.

Embyology

These cells are derived from

Function

Intramuscular Interstitial cells of Cajal (ICC-IM) are involved in mediating responses to neurotransmission.^[7] All ICC in the gastrointestinal tract express calcium-activated chloride channels encoded by the gene ANO1. These channels are activated by release of calcium in ICC and are important for both the pacemaker activity of ICC and their responses to neurotransmitters. A recent review noted that carbachol increases ICC activity through this channel.^[8][9] ANO1-knockout mice fail to produce slow waves and ANO1 channel inhibitors block slow waves.^[8]

ICC are also thought to be present in other types of smooth muscle tissues. But with few exceptions the function of these cells is not well understood and currently an area of active research.

Role in slow wave activity

ICC serve as

The frequency of ICC pacemaker activity differs in different regions of the GI tract:[10]

• 3 per minute in the stomach
• 11-12 per minute in the duodenum
• 8-9 per minute in the ileum
• 3-4 per minute in the
  colon

ICC also mediate neural input from

ICC also express mechano-sensitive mechanisms that cause these cells to respond to stretch. Stretching GI muscles can affect the resting potentials of ICC and affect the frequency of pacemaker activity. Carbachol increases ICC activity through ANO1 activation.^[8][9]

ICC are also critical in the propagation of electrical slow waves. ICC form a network through which slow wave activity can propagate. If this network is broken, then 2 regions of muscle will function independently.^{[medical citation needed]}

Pathology

ICCs are thought to be the cells from which

• List of human cell types derived from the germ layers
• Telocyte, a similar, and potentially equivalent, cell

References