IMMUNOHISTOCHEMICAL CHARACTERISTICS OF HUMAN PARAGANGLION CELLS AND SENSORY CORPUSCLES ASSOCIATED WITH THE URINARY-BLADDER - A DEVELOPMENTAL-STUDY IN THE MALE FETUS, NEONATE AND INFANT

Triple label immunohistochemistry was used to study the coexistence of the catecholamine-synthesising enzymes dopamine beta-hydroxylase (DBH ) and tyrosine hydroxylase (TH) and several neuropeptides including ne uropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), somatostatin (SOM) an d galanin (GAL) as well as nitric oxide synthase (NOS) in developing p elvic paraganglion cells in a series of human male fetal, neonatal and infant specimens ranging in age from 13 wk of gestation to 3 y postna tal. 13-20 wk old fetal specimens possessed large clusters of paragang lion cells lying lateral to the urinary bladder and prostate gland whi ch were intensely DBH-immunoreactive (-IR) but lacked TH, NOS and the neuropeptides investigated. With increasing fetal age small clusters o f paraganglion cells were observed in the muscle coat of the urinary b ladder. At 23 wk of gestation occasional paraganglion cells were NOS o r NPY-IR while at 26 wk of gestation the majority of paraganglion cell s were TH-IR and a few were SOM or GAL-IR. Some postnatal paraganglia within the bladder musculature contained cells which were all VIP, SP or CGRP-IR while others displayed coexistence of NOS and NPY, SP and C GRP, or NPY and VIP. The presence of NOS in certain paraganglion cells indicates their capacity to generate nitric oxide (NO). These results show that human paraganglion cells develop different phenotypes possi bly dependent upon their location within the bladder wall. A delicate plexus of branching varicose nerves was observed in the fetal paragang lia which increased in density with increasing gestational age. The ma jority of these nerves were VIP-IR while others were CGRP, SP, NPY, NO S or GAL-IR. The presence of nerve terminals adjacent to the paragangl ion cells implies a neural influence on the functional activity of the paraganglia. Some paraganglia in the late fetal and early postnatal s pecimens contained Timofeew's sensory corpuscles, resembling pacinian corpuscles in their morphology. The central nerve fibre of these corpu scles displayed immunoreactivity for SP, CGRP and NOS, the latter indi cating a possible role for NO in afferent transmission from the urinar y bladder. In addition, a few corpuscles were penetrated by a noradren ergic nerve fibre immunoreactive for NPY and TH, which may have a modu latory role on the sensory receptor.