Postnatal development of neuropeptide Y- and calcitonin gene-related peptide-immunoreactive nerves in the rat urinary bladder

Abstract

The postnatal development of neuropeptide Y- and calcitonin gene-related peptide-immunoreactive (NPY-IR and CGRP-IR) nerve fibers in the rat urinary bladder was investigated using whole-mount preparations and cryostat sections. In newborn and 3-day-old rats, many NPY-IR nerve fibers were observed in the subserous and muscle layers. Many NPY-IR nerve cell bodies clustered at branching points of the subserous nerve bundles. Within 4 weeks after birth, these cell bodies drastically decreased in number and spread along the bundles, although the number of NPY-IR nerve fibers increased moderately. In contrast, CGRP-IR nerve fibers in newborn and 3-day-old rats were less developed, and no CGRP-IR nerve cell body was observed in any rat. However, CGRP-IR nerve fiber distribution in the urinary tissues conspicuously increased within 4 weeks after birth. Especially, an increase of the infraepithelial fibers showing a meshwork appearance was prominent in the fundus and corpus of the bladder. The infra- and intraepithelial CGRP-IR nerve meshwork of the ventral wall was more dense than that of the trigone. At 4 weeks, NPY-IR and CGRP-IR nerves were similar to those of the adult rat (8-12 weeks old). The present study suggests a correlation between the development of the peripheral nervous system in the urinary bladder and maturation of micturition behavior in the rat.

P2X2 and P2X3 receptor expression in postnatal and adult rat urinary bladder and lumbosacral spinal cord

“…This reorganization leads to downregulation of primitive spinal mechanisms and upregulation of mature supraspinal pathways (12, 13). Previous studies have suggested the importance of neuroactive compounds in the process of maturation of the micturition reflexes during prenatal and early postnatal development (19,26,41).There is a substantial body of literature that supports a functional role for ATP in the modality of mechanotransduction in the urinary bladder (7, 57). ATP can be produced and released from the urothelium in response to stretch (21,45,46), and this release can be augmented in urothelial cells from patients with interstitial cystitis (IC) (45) and benign prostatic hyperplasia (46).…”

“…This reorganization leads to downregulation of primitive spinal mechanisms and upregulation of mature supraspinal pathways (12, 13). Previous studies have suggested the importance of neuroactive compounds in the process of maturation of the micturition reflexes during prenatal and early postnatal development (19,26,41).…”

Developmental expression of glial cell‐line derived neurotrophic factor, neurturin, and their receptor mRNA in the rat urinary bladder

“…For whole-mount staining, embryos were incubated in 100% dimethyl sulfoxide for 3 hours at room temperature [Iuchi et al, 1994]. They were pretreated with 3% normal bovine serum for 2 hours at room temperature.…”

Maturation of stretch‐induced contractile activity and its muscarinic regulation in isolated whole bladder strips from rat

“…Pharmacologically the responses to KCl, 6,7 Carbachol (CA), 7 ATP, 6,7 and Substance P 6 were significantly increased in neonatal bladders from different species. Further reports have been made on age-dependent evolutions in endothelin receptors, 8 neuropeptide Y-and CGRP-related immunoreactive nerve fibres, 9 purinoreceptor expression 10 and calcium-handling in excitation-contraction coupling. 11 (For reviews on age-dependent evolutions in autonomic bladder function, see Refs.…”