Activity within specific enteric neurochemical subtypes is correlated with distinct patterns of gastrointestinal motility in the murine colon

摘要

The enteric nervous system in the large intestine generates two important patterns relating to motility: /) propagating rhythmic peristaltic smooth muscle contractions referred to as colonic migrating motor complexes (CM-MCs) and 2) tonic inhibition, during which colonic smooth muscle contractions are suppressed. The precise neurobiological substrates underlying each of these patterns are unclear. Using transgenic animals expressing the genetically encoded calcium indicator GCaMP3 to monitor activity or the optogenetic actuator channelrhodopsin (ChR2) to drive activity in defined enteric neuronal subpopulations, we provide evidence that cholinergic and nitrergic neurons play significant roles in mediating CMMCs and tonic inhibition, respectively. Nitrergic neurons neuronal nitric oxide synthase (nNOS)-positive neurons expressing GCaMP3 exhibited higher levels of activity during periods of tonic inhibition than during CMMCs. Consistent with these findings, optogenetic activation of ChR2 in nitrergic neurons depressed ongoing CMMCs.