Ultrastructural changes in myenteric ganglia in gastro-intestinal sphincters of cat and rat after chemical sympathectomy.

Electronmicroscopic studies are made of the myenteric ganglia from the lower esophageal, pyloric and ileo-caecal sphincters of cats and rats after intravenous injection of 6-hydroxydopamine. The changes occur as early as the 30th min after treatment and comprise the adrenergic varicosities in all three sphincters studied. The destructive process develops very quickly and on the 4th hour it comprises all adrenergic varicosities. Later during the study there occur degenerative changes along the axons as well. Although each stage in the study is characterized by predomination of a certain change, there is some asynchronousness in the changes. The changes are characteristic of the adrenergic varicosities in the myenteric ganglia of all three sphincters, but there is a difference in the dynamics and extent of the damage.