Function of Interstitial Cells of Cajal in the Rabbit Portal Vein

Abstract

Abstract-Interstitial cells of Cajal (ICCs) were identified in the intact fixed media of the rabbit portal vein (RPV) using c-kit staining. The following experiments were performed using single cell preparations of the enzyme-dispersed vessel. Surviving contacts between the processes of single ICCs and the bodies of smooth muscle cells (SMCs) were observed in electron micrographs and by confocal microscopy. Spontaneous rhythmical [Ca 2ϩ ] i oscillations were observed in ICCs after loading with the calcium indicator fluo-3 and were associated with depolarizations of the ICCs recorded by tight-seal patch pipette. To investigate signal transmission from ICCs to SMCs in dispersed cell pairs, or within small surviving fragments of the ICC network, an ICC was stimulated under voltage-clamp, while changes in [Ca 2ϩ ] i in the stimulated cell as well as in a closely adjacent SMC or ICCs were monitored using fast x-y confocal imaging of fluo-3 fluorescence. After stimulation of single voltage-clamped ICC by a depolarizing step similar in duration to depolarizations associated with spontaneous [Ca 2ϩ ] i oscillations, a depolarization and transient elevation of [Ca 2ϩ ] i was observed in a closely adjacent SMCs after a delay of up to 4 seconds. In contrast, signal transmission from ICC to ICC was much faster, the delay being less than 200 ms. These results suggest that the an ICC may, in addition to generating an electrical signal (such as a slow wave) and thereby acting as a pacemaker for vascular SMCs of RPV, also release some unknown diffusible substance, which depolarizes the SMCs.

Novel type of interstitial cell (Cajal-like) in human fallopian tube

“…-number (1-5, but 2-3 in most cases); -length (usualy several tens of μm [45], up to 100 μm [14,46], or even more [39]); -thickness (around or less than 0.5 μm; frequently < 0.2 μm); -aspect (moniliform, with dilations accomodating usually mitochondria); -branching (dichotomous pattern); -organization in network -labyrinthic system (processes overlapping with processes of other similar cells). Organelles considered as characteristic features for ICC or Cajal-like cells were not ordinarily described in quantitative terms.…”

“…In a series of recent papers, ICC-like cells have been claimed to occur in other organs: vas deferens [25], urethra [26][27][28], bladder [29][30][31][32][33], ureter [34,35], uterus [36,37], blood vessels [38][39][40], lymphatics [41], prostate [42,43], penis [44], mammary gland [45] and pancreas [46].…”

Interstitial cells in the vasculature

“…However, the presence of stellate shaped cells in human cerebral arteries has been described but not illustrated [28,29]. While in RPV the c-kit positive ICs can act as pacemakers [26,30] the function of the c-kit negative ICC-like cells in guinea pig resistance MA or c-kit positive ICs in mouse resistance MA is yet unclear [25,27]. In the present article we review recent progress of our group in investigating of properties of ICs in the vasculature with some references to ICs in other types of tissues.…”

“…In this review we will refer to "ICCs" in the case of the extensively described interstitial cells of Cajal located in the GI tract, in all other cases the abbreviation "ICs" (interstitial cells) will be used. Thus, ICs have been found in the rabbit urethra [13,14], guinea pig urinary bladder [15], rat, mouse and guinea pig vas deferens [16], in mouse striated muscle [17], guinea pig and human prostate [18,19], corpora spongiosum of the guinea-pig penis [20], sheep mesenteric lymphatic vessels [21], in human and rat uterus [22], human and rat exocrine pancreas [23] as well as in rabbit portal vein (RPV) and guinea pig mesenteric artery (MA) by our group [24][25][26]. Lately we have found the presence of ICs in the wall of mouse MA [27].…”

Interstitial cells of Cajal in pancreas

“…Such locations are: vas deferens [29], urethra [30], bladder [31], ureter [32,33], uterus [34]. Noteworthy, ICC-like cells were also found in vessels: arteries [35], veins [36], or lymphatics [37] (for review see ref. [38]).…”