Inhibitory transmission to the longitudinal muscle of the mouse caecum is mediated largely by nitric oxide acting via soluble guanylyl cyclase

Abstract

In this work we describe a region of mouse intestine, the caecum, in which inhibitory transmission to the longitudinal muscle is predominantly due to nitric oxide. In the presence of muscarinic receptor blockade, electrical stimulation of intramural nerves in the longitudinal muscle of the mouse caecum evoked a relaxation. The relaxation was reduced to about 25% of the control amplitude by the nitric oxide synthase inhibitor L-NMMA (NG-methyl-L-arginine), but was unaffected by D-NMMA. In the presence of the nitric oxide scavenger oxyhaemoglobin, the relaxation was reduced to less than 10% of the control amplitude. In the circular muscle of the caecum and the longitudinal muscle of the ileum,..