Identification of bladder and colon afferents in the nodose ganglia of male rats.
The sensory neurons innervating the urinary bladder and distal colon project to similar regions of the central nervous system and often are affected simultaneously by various diseases and disorders, including spinal cord injury. Anatomical and physiological commonalities between the two organs involve the participation of shared spinally derived pathways, allowing mechanisms of communication between the bladder and colon. Prior electrophysiological data from our laboratory suggest that the bladder also may receive sensory innervation from a nonspinal source through the vagus nerve, which innervates the distal colon as well. The present study therefore aimed to determine whether anatomical evidence exists for vagal innervation of the male rat urinary bladder and to assess whether those vagal afferents also innervate the colon. Additionally, the relative contribution to bladder and colon sensory innervation of spinal and vagal sources was determined. By using lipophilic tracers, neurons that innervated the bladder and colon in both the nodose ganglia (NG) and L6/S1 and L1/L2 dorsal root ganglia (DRG) were quantified. Some single vagal and spinal neurons provided dual innervation to both organs. The proportions of NG afferents labeled from the bladder did not differ from spinal afferents labeled from the bladder when considering the collective population of total neurons from either group. Our results demonstrate evidence for vagal innervation of the bladder and colon and suggest that dichotomizing vagal afferents may provide a neural mechanism for cross-talk between the organs.
Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky, 40202; Kentucky Spinal Cord Injury Research Center University of Louisville, Louisville, Kentucky, 40202.
April N
AN
Herrity
Kristofer K
KK
Rau
Jeffrey C
JC
Petruska
David P
DP
Stirling
Charles H
CH
Hubscher
D000704:Analysis of Variance; D000818:Animals; D002452:Cell Count; D002772:Cholera Toxin / Q000378:metabolism; D003106:Colon / Q000502:physiology*; D003911:Dextrans / Q000378:metabolism; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D009475:Neurons, Afferent / Q000502:physiology*; D009620:Nodose Ganglion / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D012235:Rhodamines / Q000378:metabolism; D013116:Spinal Cord; D001743:Urinary Bladder / Q000502:physiology*; D014630:Vagus Nerve / Q000378:metabolism
D003911:Dextrans; D012235:Rhodamines; C015219:fluorescein isothiocyanate dextran; C005358:tetramethylrhodamine; D002772:Cholera Toxin; D016650:Fluorescein-5-isothiocyanate
RRID: AB_1502299; RRID: AB_2307446; convergence; pelvic; vagus; visceral