Non‐Contractile Cells with Thin Processes Resembling Interstitial Cells of Cajal Found in the Wall of Guinea‐Pig Mesenteric Arteries

Abstract

Arterial interstitial cells of Cajal (ICC)‐like cells (AIL cells) with a multipolar, irregular, elongated shape and with numerous thin (often less than 1 μm), sometimes branching, processes with lengths up to ≈60 μm were isolated enzymatically from 1st to 7th order branches of guinea‐pig mesenteric artery. Some of the processes of AIL cells were growing (average speed ≈0.15 μm min−1) and their growth was blocked by 10 μM latrunculin B, an inhibitor of actin polymerisation. Staining with BODIPY phalloidin, a fluorescent dye selective for F‐actin, showed the presence of F‐actin in the processes of AIL cells. Voltage clamp of single AIL cells revealed an inward current that was four times more dense than in myocytes and was abolished by 10 μM nicardipine, and an outward current carried exclusively by potassium ions that was reduced by 1 mM 4‐aminopyridine and/or 100 nM iberiotoxin but unaffected by 10 nM dendrotoxin‐K. Imaging of intracellular ionised calcium with fluo‐4 using a laser scanning confocal microscope showed local or global calcium transients lasting several seconds in ≈28 % of AIL cells. When membrane current was recorded simultaneously, the calcium transients were found to correspond to long‐lasting transient outward currents, which occurred at potentials positive to −40 mV. Unlike myocytes, AIL cells did not contract in response to 1 mM caffeine or 5 μM noradrenaline, although they responded with a [Ca2+]i increase. The segments of intact arteries did not stain for c‐kit, a marker of ICCs. Single AIL cells stained positive for vimentin, desmin and smooth muscle myosin. The presence of ICC‐like cells is demonstrated for the first time in the media of resistance arteries.

Imaging remodeling of the actin cytoskeleton in vascular smooth muscle cells after mechanosensitive arteriolar constriction

“…The adventitial cells were often in close apposition to VSMCs and may represent adventitial fibroblasts or vascular "interstitial cells of Cajal" (ICCs) (23,24). ICCs are smooth muscle/ fibroblast-like cells that are present in the gastrointestinal tract, urinary tract, mesenteric resistance arteries, and portal vein, where they are thought to function as pacemakers, regulating the phasic activity of smooth muscle cells (23,24).…”

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]).…”

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].…”