Stress exacerbates symptoms of functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) in humans, but mechanisms contributing to symptom worsening are unknown.
These studies address stress-induced changes in the structure and function of the micturition reflex using an animal model of stress in male rats. Rats were exposed to 7 days of repeated variate stress (RVS). Target organ (urinary bladder, thymus, adrenal gland) tissues were collected and weighed following RVS. Evans blue (EB) concentration and histamine, MPO, NGF, BDNF, and CXCL12 protein content (ELISA) were measured in the urinary bladder, and somatic sensitivity of the hindpaw and pelvic regions was determined following RVS. Bladder function was evaluated using continuous, open outlet intravesical infusion of saline in conscious rats. Increases in body weight gain were significantly (p ≤ 0.01) attenuated by day 5 of RVS and adrenal weight was significantly (p ≤ 0.05) increased. Histamine, MPO, NGF, and CXCL12 protein expression was significantly (p ≤ 0.01) increased in the urinary bladder following RVS. Somatic sensitivity of the hindpaw and pelvic regions was significantly (p ≤ 0.01) increased at all monofilament forces tested (0.1 to 4 g) following RVS. Intercontraction interval, infused volume, and void volume were significantly (p ≤ 0.01) decreased following RVS. These studies demonstrate increased voiding frequency, histamine, MPO, NGF and CXCL12 bladder content and somatic sensitivity after RVS suggesting an inflammatory component to stress-induced changes in bladder function and somatic sensitivity.
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Merrill L, Malley SE, Vizzard MA. Are you the author?
Reference: Am J Physiol Regul Integr Comp Physiol. 2013 May 8. Epub ahead of print.
doi: 10.1152/ajpregu.00089.2013
PubMed Abstract
PMID: 23657640
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