Immunohistochemical characterization of neurons in the vestibular ganglion (Scarpa’s ganglion) of the pig

The study was carried out on three 4-month old female pigs. All the animals were deeply anesthetized and transcardially perfused with 4% buffered paraformaldehyde (pH 7.4). Vestibular ganglia (VG) were collected and processed for double-labelling immunofluorescence method. The preparations were examined under the Zeiss LSM 710 confocal microscope equipped with adequate filter blocks. Neurons forming VG were round or oval in shape with a round nucleus in the center. The majority of them (58%) were medium (M) (31-50 μm in diameter) while 28 % and 14% were small (S) (up to 30 μm in diameter) or large (L) (above 50 μm in diameter) in size, respectively. Double-labeling immunofluorescence revealed that VG neurons stained for CGRP (approx. 81%; among them 70.5%, 26.2% and 3.3% were M, S and L in size, respectively), VACHT (57%; 63% M, 24% S, 13% L), Met-Enk (25%; 60% M, 12% S, 28% L), VIP (20%; 88% M, 6% S, L), NPY (15%; 67% M, 20% S, 13% L), GAL (15%; 74% M, 21% S, 5% L), SP (12%; 69% M, 25% S, 6% L) and NOS-positive (12%; 50% S, 50% M). The most abundant populations of intraganglionic nerve fibers were those which stained for CGRP or Met-Enk, whereas only single SP- or NOS-positive nerve terminals were observed.