TY - JOUR
T1 - Projections of excitatory and inhibitory motor neurones to the circular and longitudinal muscle of the guinea pig colon
AU - Neunlist, Michel
AU - Michel, Klaus
AU - Aubé, Anne Catherine
AU - Galmiche, Jean
AU - Schemann, Michael
N1 - Funding Information:
The first two authors contributed equally to this study, which was supported by Deutsche Forschungsgemeinschaft SFB 280
PY - 2001
Y1 - 2001
N2 - The aim of this study was to identify myenteric pathways to the circular and longitudinal muscle of the guinea pig proximal colon. To identify excitatory and inhibitory muscle motoneurones, we applied the neuronal retrograde tracer DiI onto the circular or longitudinal muscle layer and performed additional immunohistochemistry for nitric oxide synthase (NOS) and choline acetyltransferase (ChAT). On average 166±81 circular muscle motoneurones (CMMN) and 100±74 longitudinal muscle motoneurones (LMMN) were labelled by DiI tracing. Myenteric pathways innervating the muscle were either ascending (DiI-labelled neurones with oral projections) or descending (DiI-labelled neurones with anal projections). The circular muscle was preferentially innervated by ascending pathways (66.0±9.1%). Most ascending CMMN were ChAT-positive (87.2±8.5%), whereas descending CMMN were mainly NOS-positive (82.3±14.6%). Most ascending (62.2±11.1%) and descending (82.0±12.5%) CMMN had circumferential projection preferences (circumferential projections were longer than projections along the longitudinal gut axis). In contrast to the polarised projections to the circular muscle, the longitudinal muscle was equally innervated by ascending (46.2±15.1%) and descending (53.9±15.1%) neurones. Ascending and descending pathways to the longitudinal muscle consisted predominantly of ChAT-positive neurones (98.1±1.9% and 68.0±8.5%, respectively), and both pathways had prominent longitudinal projection preferences. Only 25.5% of the descending LMMN were NOS-positive. In conclusion, the circular muscle in the proximal colon is innervated by descending inhibitory (NOS-positive neurones) and ascending excitatory (ChAT-positive neurones) pathways. In contrast, the longitudinal muscle is primarily innervated by ascending and descending excitatory motoneurones, and only a small proportion of the descending pathway consisted of inhibitory motoneurones.
AB - The aim of this study was to identify myenteric pathways to the circular and longitudinal muscle of the guinea pig proximal colon. To identify excitatory and inhibitory muscle motoneurones, we applied the neuronal retrograde tracer DiI onto the circular or longitudinal muscle layer and performed additional immunohistochemistry for nitric oxide synthase (NOS) and choline acetyltransferase (ChAT). On average 166±81 circular muscle motoneurones (CMMN) and 100±74 longitudinal muscle motoneurones (LMMN) were labelled by DiI tracing. Myenteric pathways innervating the muscle were either ascending (DiI-labelled neurones with oral projections) or descending (DiI-labelled neurones with anal projections). The circular muscle was preferentially innervated by ascending pathways (66.0±9.1%). Most ascending CMMN were ChAT-positive (87.2±8.5%), whereas descending CMMN were mainly NOS-positive (82.3±14.6%). Most ascending (62.2±11.1%) and descending (82.0±12.5%) CMMN had circumferential projection preferences (circumferential projections were longer than projections along the longitudinal gut axis). In contrast to the polarised projections to the circular muscle, the longitudinal muscle was equally innervated by ascending (46.2±15.1%) and descending (53.9±15.1%) neurones. Ascending and descending pathways to the longitudinal muscle consisted predominantly of ChAT-positive neurones (98.1±1.9% and 68.0±8.5%, respectively), and both pathways had prominent longitudinal projection preferences. Only 25.5% of the descending LMMN were NOS-positive. In conclusion, the circular muscle in the proximal colon is innervated by descending inhibitory (NOS-positive neurones) and ascending excitatory (ChAT-positive neurones) pathways. In contrast, the longitudinal muscle is primarily innervated by ascending and descending excitatory motoneurones, and only a small proportion of the descending pathway consisted of inhibitory motoneurones.
KW - DiI
KW - Enteric nervous system
KW - Guinea pig
KW - Tracing
UR - http://www.scopus.com/inward/record.url?scp=0035725172&partnerID=8YFLogxK
U2 - 10.1007/s004410100387
DO - 10.1007/s004410100387
M3 - Article
C2 - 11572085
AN - SCOPUS:0035725172
SN - 0302-766X
VL - 305
SP - 325
EP - 330
JO - Cell and Tissue Research
JF - Cell and Tissue Research
IS - 3
ER -