Regional distribution of autonomic nerves in guinea pig uterus

Uterine adrenergic and cholinergic nerves were examined histochemically and chemically in combination with surgical denervation. There was a clear regional variation with a greater number of axon terminals in the tubal end of the uterine horn and in the cervix compared to the remainder (major part) of the uterine horn. No cholinergic nerves were found in the uterus but were abundant around the uterine artery and its primary ramifications. Clusters of ganglion cells were located near the cervix: the majority were acetylcholinesterase positive, whereas the remainder stored catecholamines. Unexpectedly, the suspensory ligament (connecting the tubal end of the uterine horn with the two lower ribs) was found to contain an extensive number of adrenergic nerves. The major part of the uterine horns, as well as the cervix, was innervated mainly from two sources contributing almost equally: the paracervical ganglia (short adrenergic neurons) and postganglionic fibers running in the hypogastric nerves. A restricted area at the tubal end of the uterus received most of its via the suspensory ligament.