Journal of Neuroscience, Vol 10, 1943-1951, Copyright © 1990 by Society for Neuroscience
Morphological plasticity in efferent pathways to the urinary bladder of the rat following urethral obstruction
WD Steers, J Ciambotti, S Erdman and WC de Groat
Department of Pharmacology, University of Pittsburgh School of Medicine, Pennsylvania 15261.
Partial urethral ligation in female Wistar rats produces changes in the
neural control of the lower urinary tract including bladder hyperactivity
and facilitation of a spinal micturition reflex pathway. To gain insight
into the mechanisms underlying these changes, axonal tracing studies were
conducted to examine the postganglionic efferent limb of the micturition
reflex pathway which originates in the major pelvic ganglion (MPG). Forty
microliters of the tracer Fluoro-Gold (4%) were injected into the right
side of the bladder in urethral-obstructed (n = 10) and control (n = 4)
rats 6 weeks after urethral ligation or sham surgery. As a control Fast
blue (40 microliters, 5%) was injected into the colon to label neurons in
the MPG innervating the intestine. Obstructed rats exhibited a 6-fold
increase (p less than 0.001) in bladder weight (0.848 gm) compared to
controls (0.148 gm). A significant increase (p less than 0.001) in the size
of labeled bladder postganglionic neurons in the MPG was noted in
obstructed rats (576.4 microns 2, n = 4) as compared to controls (299.6
microns 2). However, labeled, colon postganglionic neurons in the MPG in
obstructed (312.9 microns 2) rats were not enlarged compared to controls
(359.4 microns 2). Neuronal hypertrophy was not associated with a change in
the number of labeled MPG neurons in control and obstructed
groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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