Expression of corticotropin-releasing factor and CRF receptors in micturition pathways after cyclophosphamide-induced cystitis

Abstract

ticotropin-releasing factor (CRF) is a prominent neuropeptide involved in micturition reflexes, and different roles in these reflexes have been suggested. These studies examined the expression of CRF in the urinary bladder and lumbosacral sacral parasympathetic nucleus (SPN) in response to cyclophosphamide (CYP)-induced cystitis (4 h, 48 h, or chronic) in rats. The expression of CRF receptors, CRF 1 and CRF2, was examined in urinary bladder from control and CYP-treated rats. Urinary bladder and lumbosacral spinal cord were harvested from rats killed by isoflurane (4%) and thoracotomy. CRF protein expression in whole urinary bladders significantly (P Յ 0.01) increased with 48 h or chronic CYP treatment. CRF immunoreactivity (IR) was increased significantly (P Յ 0.01) in the urothelium and SPN after CYP treatment. CRF IR nerve fibers increased in density in the suburothelial plexus and detrusor smooth muscle whole mounts with CYP-induced cystitis. CRF 2 receptor transcript was expressed in the urothelium or detrusor smooth muscle, and CRF2 receptor expression increased in whole bladder with CYP-treatment, whereas no CRF1 receptor transcript was expressed in either urothelium or detrusor. Immunohistochemical studies demonstrated CRF 2 IR in urinary bladder nerve fibers and urothelial cells from control animals, whereas no CRF 1 IR was observed. These studies demonstrated changes in the expression of CRF in urinary bladder and SPN region with CYPinduced cystitis and CRF receptor (CRF 2) expression in nerve fibers and urothelium in control rats. CRF may contribute to urinary bladder overactivity and altered sensory processing with CYP-induced cystitis. inflammation; sacral parasympathetic nucleus; urothelium; enzymelinked immunosorbet assay THE CHEMICALLY (cyclophosphamide, CYP) induced bladder inflammation model is associated with alterations in neurochemical (57, 61), electrophysiological (66), organizational (62), and functional properties (14) of micturition pathways. These changes may be mediated by chemical mediators (e.g., neurotrophins, cytokines, neuropeptides) produced in the bladder, spinal cord, or dorsal root ganglia with cystitis (5, 27, 57, 59, 61).Corticotropin-releasing factor (CRF) is of particular relevance in the rat, since it is present in descending projections from the pontine micturition center or more specifically from Barrington's nucleus to the sacral parasympathetic nucleus (SPN; see Refs. 30,31,49,56). Historically, Barrington's nucleus has been viewed as the supraspinal switching center that regulates storage and elimination of urine (25,33,41). Recent studies have led to the suggestion that Barrington's nucleus may contain neurons that control a broad range of pelvic organ functions (28,29,34,38,55). CRF is prominently expressed in the descending pathway from Barrington's nucleus to the SPN in the lumbosacral spinal cord, and prominent CRF immunoreactivity (IR) is expressed in the SPN of adult rats (37,53,54). Our recent studies have demonstrated an age-dependent upregulation of CRF IR ...

Phosphorylation of extracellular signal-regulated kinases in urinary bladder in rats with cyclophosphamide-induced cystitis

“…4B). These cells show a similar morphology to mast cells and macrophages previously described in the urinary bladder after CYP-induced cystitis (20,26). Double-labeling experiments demonstrated that these pERK-IR cells expressed the CD86 antigen (e.g., macrophages, dendritic cells) (Fig.…”

“…Cy3 was visualized with a filter with an excitation range of 560 -596 nm and an emission range from 610 -655 nm. Grayscale images acquired in tiff format here imported into MetaMorph image analysis software (version 4.5r4; Universal Imaging, Downingtown, PA) as previously described (26,58). Images were calibrated for pixel size by applying a previously created calibration file to convert all measurements from pixels to square micrometers.…”

A corticotropin-releasing factor receptor antagonist improves urodynamic dysfunction produced by social stress or partial bladder outlet obstruction in male rats

“…Other brain circuits in which CRF is prominent have not been directly associated with bladder regulation. Moreover, it is unlikely that the site of action of NBI-30775 is at the level of the bladder because neither CRF 1 receptor nor CRF 1 immunoreactivity are present in bladder (19). The finding that NBI-30775 prevented the urodynamic consequences of social stress without affecting CRF upregulation in Barrington's nucleus neurons indicates that it was acting at the level of the spinal cord where Barrington's nucleus neurons terminate so that the social stress-induced bladder dysfunction failed to occur in spite of elevated levels of CRF in this pathway.…”

Chronic psychological stress enhances nociceptive processing in the urinary bladder in high-anxiety rats

“…With regard to the bladder, CRF is abundantly expressed in areas involved in the control of micturition (i.e., Barrington's nucleus, lumbosacral areas of the spinal cord) and administration of various CRF receptor agonists and antagonists alters cystometric parameters [38,39,40]. Following stress or bladder inflammation, increases in CRF-IR and/or CRF2 receptor expression have been detected in these areas and in the bladder itself [41,42]. These converging lines of evidence implicate the CRF system as a potential mediator of stress-induced bladder hyperalgesia as well.…”