INCREASED EXPRESSION OF SUBSTANCE-P RECEPTOR-ENCODING MESSENGER-RNA IN BLADDER BIOPSIES FROM PATIENTS WITH INTERSTITIAL CYSTITIS

Objectives To determine whether substance P (SP, also known as neuroki nin 1, NK1) receptors are differentially expressed in bladder biopsies from patients with interstitial cystitis (IC) compared with matched c ontrols. Materials and methods Cold-cup biopsies were taken during rou tine diagnostic cystoscopy. NK1-receptor expression was assessed using a quantitative analysis of NK1-receptor-encoding mRNA in bladder biop sies from patients and controls using in situ hybridization histochemi stry (ISHH) combined with autoradiographic image analysis. Results Aut oradiographic signal indicating the presence of NK1-encoding mRNA was localized to detrusor muscle, urothelium and vascular structures, In t he bladder vasculature, the signal was predominantly associated with e ndothelial cells, NK1 receptor-encoding mRNA within the vascular endot helium was increased in the biopsies obtained from patients with IC. C onclusion Increased levels of NK1 receptor-encoding mRNA within the bl adder vascular endothelium suggests the up-regulation of NK1 receptor as a putative factor in the pathogenesis of pain related to IC. Increa sed responsiveness to SP released from the perivascular sensory termin als may result in a local cascade of neurogenic inflammatory responses which the pathophysiological changes, including pain, characteristic of IC.