One hundred years of interstitial cells of Cajal

This review is a portrayal of the evolution of ideas involving the intersti tial cells of Cajal in changing disguises as dull fibroblasts, not very exc iting Schwann cells, or perhaps quite important, though primitive neurons. However, today unmasked (we believe), they reveal themselves as myoid cells , a role that, judging by current interest, is far more exciting than forme r ones. Close to 500 publications from 1860-1999 have contributed to the discussion in one way or the other. This literature contains a wealth of correct obse rvations but obviously also wrong interpretations, which are seen as a resu lt of too blind a belief in specificities of visualization methods, combine d with a desire to interpret even the hidden detail. It has been my objective to attempt to trace the origins of viable ideas, a nd I have therefore focused on relatively few authors. The most recent deve lopment from 1980 until today is so well covered by easily accessible revie ws that I have resorted to a mere, but hopefully complete, list of them. Modern ICC'ists have so far been caught in the external muscle of the gut a nd kept their hands off its internal affairs. However, while working my way through the literature it struck me that a number of recent studies may pr ovide the elements of a plausible model for the villous contraction mechani sm. In the present context, an important point is that the very first publi shed interstitial "neurons" from Cajal's hand-of the intestinal villus, 188 9-may achieve new significance as a possible correlate to the regulatory IC C of the intestinal muscularis. Partly to make this point, I have taken the liberty of giving a short account of recent results from our lab. Microsc. Res. Tech. 47:223-238, 1999. (C) 1999 Wiley-Liss, Inc.