vasoactive-intestinal-peptide and Reflex--Abnormal

We have previously demonstrated nerve growth factor (NGF) regulation of pituitary adenylate cyclase-activating polypeptide (PACAP)/receptors in bladder reflex pathways using a transgenic mouse model of chronic NGF overexpression in the bladder using the urothelial-specific uroplakin II promoter. We have now explored the contribution of target-derived NGF in combination with cyclophosphamide (CYP)-induced cystitis to determine whether additional changes in neuropeptides/receptors are observed in micturition reflex pathways due to the presence of additional inflammatory mediators in the urinary bladder. Quantitative PCR was used to determine PACAP/vasoactive intestinal polypeptide (VIP), substance P, galanin, and receptor transcript expression in the urinary bladder (urothelium, detrusor) in mice with overexpression of NGF in the urothelium (NGF-OE) and wild-type (WT) mice with CYP-induced cystitis (4 h, 48 h, and chronic). With CYP-induced cystitis (4 h), WT and NGF-OE mice exhibited similar changes in galanin transcript expression in the urothelium (30-fold increase) and detrusor (threefold increase). In contrast, PACAP, VIP, and substance P transcripts exhibited differential changes in WT and NGF-OE with CYP-induced cystitis. PAC1, VPAC1, and VPAC2 transcript expression also exhibited differential responses in NGF-OE mice that were tissue (urothelium vs. detrusor) and CYP-induced cystitis duration-dependent. Using conscious cystometry, NGF-OE mice treated with CYP exhibited significant (p ≤ 0.01) increases in voiding frequency above that observed in control NGF-OE mice. In addition, no changes in the electrical properties of the major pelvic ganglia neurons of NGF-OE mice were detected using intracellular recording, suggesting that the urinary bladder phenotype in NGF-OE mice is not influenced by changes in the efferent limb of the micturition reflex. These studies are consistent with target-derived NGF and other inflammatory mediators affecting neurochemical plasticity and the reflex function of micturition pathways.

Topics: Animals; Cyclophosphamide; Cystitis; Disease Progression; Galanin; Gene Expression Regulation; Mice; Mice, Inbred C57BL; Mice, Transgenic; Muscle, Smooth; Nerve Growth Factor; Organ Specificity; Pituitary Adenylate Cyclase-Activating Polypeptide; Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; Receptors, Vasoactive Intestinal Peptide, Type II; Receptors, Vasoactive Intestinal Polypeptide, Type I; Recombinant Fusion Proteins; Reflex, Abnormal; RNA, Messenger; Substance P; Urinary Bladder; Urination; Urothelium; Vasoactive Intestinal Peptide

These studies examined the transcriptional and translational plasticity of three transient receptor potential (TRP) channels (TRPA1, TRPV1, TRPV4) with established neuronal and non-neuronal expression and functional roles in the lower urinary tract. Mechanosensor and nociceptor roles in either physiological or pathological lower urinary tract states have been suggested for TRPA1, TRPV1, and TRPV4. We have previously demonstrated the neurochemical, organizational, and functional plasticity in micturition reflex pathways following induction of urinary bladder inflammation using the antineoplastic agent, cyclophosphamide. More recently, we have characterized similar plasticity in micturition reflex pathways in a transgenic mouse model with chronic urothelial overexpression (OE) of nerve growth factor (NGF) and in a transgenic mouse model with deletion of vasoactive intestinal polypeptide (VIP). In addition, the micturition reflex undergoes postnatal maturation that may also reflect plasticity in urinary bladder TRP channel expression. Thus, we examined plasticity in urinary bladder TRP channel expression in diverse contexts using a combination of quantitative, real-time PCR and western blotting approaches. We demonstrate transcriptional and translational plasticity of urinary bladder TRPA1, TRPV1, and TRVP4 expression. Although the functional significance of urinary bladder TRP channel plasticity awaits further investigation, these studies demonstrate context- (inflammation, postnatal development, NGF-OE, VIP deletion) and tissue-dependent (urothelium + suburothelium, detrusor) plasticity.

Topics: Aging; Animals; Cyclophosphamide; Cystitis; Disease Progression; Female; Gene Expression Regulation; Mice; Mice, Knockout; Mice, Transgenic; Muscle, Smooth; Nerve Growth Factor; Organ Specificity; Protein Biosynthesis; Rats; Rats, Wistar; Recombinant Fusion Proteins; Reflex, Abnormal; Transcription, Genetic; Urinary Bladder; Urination; Urothelium; Vasoactive Intestinal Peptide

Vasoactive intestinal polypeptide (VIP) is an immunomodulatory neuropeptide widely distributed in neural pathways that regulate micturition. VIP is also an endogenous anti-inflammatory agent that has been suggested for the development of therapies for inflammatory disorders. In the present study, we examined urinary bladder function and hindpaw and pelvic sensitivity in VIP(-/-) and littermate wildtype (WT) controls. We demonstrated increased bladder mass and fewer but larger urine spots on filter paper in VIP(-/-) mice. Using cystometry in conscious, unrestrained mice, VIP(-/-) mice exhibited increased void volumes and shorter intercontraction intervals with continuous intravesical infusion of saline. No differences in transepithelial resistance or water permeability were demonstrated between VIP(-/-) and WT mice; however, an increase in urea permeability was demonstrated in VIP(-/-) mice. With the induction of bladder inflammation by acute administration of cyclophosphamide, an exaggerated or prolonged bladder hyperreflexia and hindpaw and pelvic sensitivity were demonstrated in VIP(-/-) mice. The changes in bladder hyperreflexia and somatic sensitivity in VIP(-/-) mice may reflect increased expression of neurotrophins and/or proinflammatory cytokines in the urinary bladder. Thus, these changes may further regulate the neural control of micturition.

Topics: Animals; Cystitis; Female; Humans; Hyperalgesia; Mice; Mice, Knockout; Pain Measurement; Reflex, Abnormal; Urinary Bladder; Urination; Vasoactive Intestinal Peptide

The urethras from 1 patient with cervical (C1-2) and 2 patients with thoracic (T10) spinal cord lesions were studied histochemically and immunohistochemically for adrenergic and vasoactive intestinal polypeptide-immunoreactive nerves. Dense vasoactive intestinal polypeptide-immunoreactive but not adrenergic nerves were found in the urethral smooth muscle, around the blood vessels and at the base of the mucosa in the patients with thoracic lesions. In contrast, adrenergic but not vasoactive intestinal polypeptide-immunoreactive nerves were found associated with the smooth muscle of the urethra and around the blood vessels in the patient with a cervical lesion. In patients with cervical or thoracic lesions neither adrenergic nor vasoactive intestinal polypeptide-immunoreactive nerves were found around striated muscle fibers of the intrinsic external urethral sphincter. The results are discussed in relation to the possible function of these nerves in the urethra of patients with autonomic dysreflexia and detrusor-sphincter dyssynergia.

Topics: Adult; Autonomic Nervous System Diseases; Catecholamines; Cervical Vertebrae; Humans; Male; Middle Aged; Reflex, Abnormal; Spinal Cord Injuries; Thoracic Vertebrae; Urethra; Vasoactive Intestinal Peptide

The distribution of nerves containing vasoactive intestinal polypeptide (VIP) in the hyper-reflexic neuropathic bladder was investigated using immunocytochemistry and radioimmunoassay. Biopsy specimens were taken from the bladders of 21 patients with urodynamically proven detrusor hyper-reflexia and from 20 control patients with no urodynamic abnormality. The results showed a reduction in the number of VIP immunoreactive nerves and a reduction in VIP concentration in the hyper-reflexic bladder when compared with control samples.

Topics: Adult; Aged; Female; Humans; Male; Middle Aged; Radioimmunoassay; Reflex, Abnormal; Urinary Bladder; Urinary Bladder, Neurogenic; Vasoactive Intestinal Peptide