| First Author | Beckett EA | Year | 2002 |
| Journal | J Physiol | Volume | 543 |
| Issue | Pt 3 | Pages | 871-87 |
| PubMed ID | 12231645 | Mgi Jnum | J:105989 |
| Mgi Id | MGI:3617107 | Doi | 10.1113/jphysiol.2002.021915 |
| Citation | Beckett EA, et al. (2002) Loss of enteric motor neurotransmission in the gastric fundus of Sl/Sl(d) mice. J Physiol 543(Pt 3):871-87 |
| abstractText | Studies of W/W(V) mice, which lack intramuscular interstitial cells of Cajal (IC-IM), have suggested that IC-IM act as mediators of enteric motor neurotransmission in the gastrointestinal tract. We have studied Sl/Sl(d) mice, which lack the ability to make membrane-bound stem cell factor, to determine the consequences of inappropriate stem cell factor expression on IC-IM populations and on enteric motor neurotransmission. IC-IM were found within the circular and longitudinal muscles of the gastric fundus of wild-type mice. IC-IM were intimately associated with motor nerve terminals and nerve varicosities formed synaptic structures with these cells. IC-IM were also connected with neighbouring smooth muscle cells via gap junctions. Immunohistochemistry and electron microscopy showed that IC-IM were absent from fundus muscles of Sl/Sl(d) mice, but the density of excitatory and inhibitory nerves was not significantly different than in wild-type muscles. Loss of IC-IM was associated with decreased membrane noise (unitary potentials) and significant reductions in post-junctional excitatory and inhibitory enteric nerve responses. Reductions in neural responses were not due to defects in smooth muscle cells as responses to exogenous ACh and K(+)-induced depolarization were normal in Sl/Sl(d) mice. Responses to neurally released ACh were revealed in Sl/Sl(d) mice by inhibiting ACh breakdown with the acetylcholinesterase inhibitor neostigmine. Inhibitory nerve stimulation elicited inhibitory junction potentials (IJPs) and relaxations in wild-type mice. IJPs were reduced in amplitude and relaxation responses were absent in Sl/Sl(d) mice. These observations suggest that membrane-bound stem cell factor is essential for development of IC-IM and that the close, synaptic-like relationship between nerve terminals and IC-IM may be the primary site of innervation by enteric motor neurons in gastric muscles. |
