Wood SK, Baez MA, Bhatnagar S, Valentino RJ. Social stress-induced bladder dysfunction: potential role of corticotropin-releasing factor. Am J Physiol Regul Integr Comp Physiol 296: R1671-R1678, 2009. First published May 11, 2009 doi:10.1152/ajpregu.91013.2008.-Psychological stress can impact on visceral function with pathological consequences, although the mechanisms underlying this are poorly understood. Here we demonstrate that social stress produces marked changes in bladder structure and function. Male rats were subjected to repeated (7 days) social defeat stress using the resident-intruder model. Measurement of the voiding pattern indicated that social stress produced urinary retention. Consistent with this, bladder size was increased in rats exposed to social stress. Moreover, this was negatively correlated to the latency to assume a subordinate posture, implying an association between passive behavior and bladder dysfunction. In vivo cystometry revealed distinct changes in urodynamic function in rats exposed to social stress, including increased bladder capacity, micturition volume, intermicturition interval, and the presence of non-micturition-related contractions, resembling overactive bladder. In contrast to social stress, repeated restraint (7 days) did not affect voiding, bladder weight, or urodynamics. The stress-related neuropeptide corticotropin-releasing factor (CRF) is present in spinal projections of Barrington's nucleus that regulate the micturition reflex and has an inhibitory influence in this pathway. Social stress, but not restraint, increased the number of CRF-immunoreactive neurons in Barrington's nucleus. Additionally, social stress increased CRF mRNA in Barrington's nucleus. Together, the results imply that social stress-induced CRF upregulation in Barrington's nucleus neurons results in urinary retention and, eventually, bladder dysfunction, perhaps as a visceral component of a behavioral coping response. This mechanism may underlie dysfunctional voiding in children and/or contribute to the development of stress-induced bladder disorders in adulthood.Barrington's nucleus; social defeat; micturition; cystometry; resident intruder CHRONIC OR REPEATED STRESS has numerous adverse psychological and physiological consequences (33). The mechanisms by which stress produces adverse effects have been studied in rodents using a variety of stressors. However, many of these stressors lack ethological validity (i.e., footshock). One stressor that is more ethologically relevant and is currently being used to model stress-related pathology involves social defeat (44). This model, in which a rodent is forced into submission by a larger male conspecific, has been used by several groups to examine behavioral and endocrine consequences of social stress (3,17,24,39,44). A visceral effect of social stress that is often reported, but has not been systematically investigated, is urinary retention that can develop into bladder hypertrophy and even nephropathy due to reflux (10,16,29). The neural processes t...

Neural circuits that allow for reciprocal communication between the brain and viscera are critical for coordinating behavior with visceral activity. At the same time, these circuits are positioned to convey signals from pathologic events occurring in viscera to the brain, thereby providing a structural basis for comorbid central and peripheral symptoms. In the pons, Barrington's nucleus and the norepinephrine (NE) nucleus, locus coeruleus (LC), are integral to a circuit that links the pelvic viscera with the forebrain and coordinates pelvic visceral activity with arousal and behavior. Here, we demonstrate that a prevalent bladder dysfunction, produced by partial obstruction in rat, has an enduring disruptive impact on cortical activity through this circuit. Within 2 weeks of partial bladder obstruction, the activity of LC neurons was tonically elevated. LC hyperactivity was associated with cortical electroencephalographic activation that was characterized by decreased low-frequency (1-3 Hz) activity and prominent theta oscillations (6 -8 Hz) that persisted for 4 weeks. Selective lesion of the LC-NE system significantly attenuated the cortical effects. The findings underscore the potential for significant neurobehavioral consequences of bladder disorders, including hyperarousal, sleep disturbances, and disruption of sensorimotor integration, as a result of central noradrenergic hyperactivity. The results further imply that pharmacological manipulation of central NE function may alleviate central sequelae of these visceral disorders.Barrington's nucleus ͉ bladder obstruction ͉ electroencephalographic activity ͉ locus coeruleus O veractive bladder is a prevalent disorder, affecting 17% of the population and negatively impacting quality of life (1). Partial bladder obstruction is a common cause of overactive bladder in males and is used to model overactive bladder in laboratory animals (2). Whereas the structural and functional changes induced in bladder by partial obstruction are well studied (3, 4), the impact on brain function has been neglected. The potential for central consequences of bladder dysfunctions exists because neural circuits are present that communicate pelvic visceral status to the brain so that behavior can be coordinated with visceral functions. Barrington's nucleus (the pontine micturition center) and the locus coeruleus (LC) are integral components of a circuit that performs this task (5). Barrington's nucleus neurons project to spinal preganglionic parasympathetic neurons, where they regulate activity of the bladder and other pelvic viscera (6). These projections form the efferent limb of the micturition reflex, in which Barrington's nucleus neurons are activated by bladder distention and in response, initiate bladder contraction (7). The same Barrington's nucleus neurons project to the LC, a major norepinephrine (NE)-containing nucleus with divergent efferent projections that densely innervate the forebrain (8, 9). Among its functions, the LC regulates arousal, shifts in attention, and involv...

We studied how the nervous system selects between noxious stimulus-evoked withdrawals and micturition, movements that are necessary for survival but use overlapping muscles and therefore cannot occur simultaneously. In lightly anesthetized rats, micturition was favored, because noxious stimulation never interrupted micturition, whereas withdrawals were suppressed during voiding.