Distribution and immunohistochemical characterisation of paracervical neurons innervating the oviduct in the pig.

The present study was aimed at disclosing the distribution of paracervical neurons projecting to the ampulla and isthmus of the porcine oviduct and the pattern(s) of co-existence of tyrosine hydroxylase (TH), dopamine beta-hydroxylase (D beta H), neuropeptide Y (NPY), substance P (SP), calcitonin gene-related peptide (CGRP) and nitric oxide synthase (NOS) within these nerve cell bodies. The fluorescent retrograde tracer Fast Blue (FB) was injected into the wall of the ampullar (n = 3) and isthmal (n = 3) part of the organ in six sexually immature female pigs. After a survival period of three weeks paracervical ganglia (PCG) were collected. 10 microns-thick cryostat sections of the ganglia were examined for the presence of FB-positive (FB+) nerve cells under the fluorescent microscope. Tracered neurons were counted in every third section and processed for double-labelling immunofluorescence according to the method of Wessendorf and Elde. 78.6% of FB+ neurons were projecting to the isthmus while 21.4% of the studied population innervated the ampulla of the oviduct. Double-labelling immunofluorescence revealed the existence of the following different chemically coded subpopulations of the studied perikarya: TH+/D beta H+, TH+/NPY+, TH+/NOS+, TH+/NOS-, SP-/NOS+, SP+/CGRP+.