Bladder Capacity is a Biomarker for a Bladder Centric versus Systemic Manifestation in Interstitial Cystitis/Bladder Pain Syndrome.

PURPOSE: Interstitial cystitis/bladder pain syndrome presents a significant clinical challenge due to symptom heterogeneity and the myriad associated comorbid medical conditions. We recently reported that diminished bladder capacity may represent a specific interstitial cystitis/bladder pain syndrome subphenotype. The objective of this study was to investigate the relationship between anesthetic bladder capacity, and urological and nonurological clinical findings in a cohort of patients with interstitial cystitis/bladder pain syndrome who had undergone therapeutic urinary bladder hydrodistention. MATERIALS AND METHODS: This is a retrospective chart review of prospectively collected data on women diagnosed with interstitial cystitis/bladder pain syndrome between 2011 and 2015 who underwent bladder hydrodistention. Assessments in each patient included a detailed history and physical examination, ICPI (Interstitial Cystitis Problem Index), ICSI (Interstitial Cystitis Symptom Index) and PUF (Pelvic Pain and Urgency/Frequency Patient Symptom Scale). Bladder capacity was determined during bladder hydrodistention with the patient under general anesthesia. RESULTS: Mean age was 45.8 years and mean bladder capacity was 857 ml in the 110 enrolled patients. We found a significant inverse correlation between bladder capacity and scores on 3 gold standard interstitial cystitis/bladder pain syndrome metrics, including ICPI (p = 0.0014), ICSI (p = 0.0022) and PUF (p = 0.0009) as well as urination frequency (p = 0.0025). Women with higher bladder capacity were significantly more likely to report depression (p = 0.0059) and irritable bowel syndrome (p = 0.022). CONCLUSIONS: Low bladder capacity while under anesthesia was significantly associated with high symptom scores on 3 validated interstitial cystitis/bladder pain syndrome questionnaires as well as with urinary frequency. However, it was not associated with depression or other common systemic pain problems. These results suggest that low bladder capacity is a marker for a bladder centric manifestation of interstitial cystitis/bladder pain syndrome.

Morphine increases acetylcholine release in the trigeminal nuclear complex.

STUDY OBJECTIVES: The trigeminal nuclear complex (V) contains cholinergic neurons and includes the principal sensory trigeminal nucleus (PSTN) which receives sensory input from the face and jaw, and the trigeminal motor nucleus (MoV) which innervates the muscles of mastication. Pain associated with pathologies of V is often managed with opioids but no studies have characterized the effect of opioids on acetylcholine (ACh) release in PSTN and MoV. Opioids can increase or decrease ACh release in brainstem nuclei. Therefore, the present experiments tested the 2-tailed hypothesis that microdialysis delivery of opioids to the PSTN and MoV significantly alters ACh release. DESIGN: Using a within-subjects design and isoflurane-anesthetized Wistar rats (n=53), ACh release in PSTN during microdialysis with Ringer's solution (control) was compared to ACh release during dialysis delivery of the sodium channel blocker tetrodotoxin, muscarinic agonist bethanechol, opioid agonist morphine, mu opioid agonist DAMGO, antagonists for mu (naloxone) and kappa (nor-binaltorphimine; nor-BNI) opioid receptors, and GABAA antagonist bicuculline. MEASUREMENTS AND RESULTS: Tetrodotoxin decreased ACh, confirming action potential-dependent ACh release. Bethanechol and morphine caused a concentration-dependent increase in PSTN ACh release. The morphine-induced increase in ACh release was blocked by nor-BNI but not by naloxone. Bicuculline delivered to the PSTN also increased ACh release. ACh release in the MoV was increased by morphine, and this increase was not blocked by naloxone or nor-BNI. CONCLUSIONS: These data comprise the first direct measures of ACh release in PSTN and MoV and suggest synaptic disinhibition as one possible mechanism by which morphine increases ACh release in the trigeminal nuclei.