Dichotomizing unmyelinated afferents supplying pelvic viscera and perineum are rare in the sacral segments of the cat.
We have tested the hypothesis that referred pain of pelvic viscera is elicited by dichotomizing branches of unmyelinated primary afferents projecting via the pelvic nerve to the viscera and through the pudendal nerve to the perineum where pelvic pain is commonly referred to. Using neurophysiological techniques 588 unmyelinated single units projecting into either nerve were recorded in the ventral (n = 228) and dorsal (n = 360) root S2. In each sample only one neurone sent an axon into both nerves. Thus, dichotomizing afferents account for less than 0.5% of the afferent neurones and appear to be an unlikely explanation for referred pain in this body area.
Häbler
H J
HJ
Physiologisches Institut der Christian-Albrechts-Universität, Kiel, F.R.G.
Jänig
W
W
Koltzenburg
M
M
D000344:Afferent Pathways / Q000502:physiology*; D000818:Animals; D001369:Axons / Q000502:physiology; D002415:Cats / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D008297:Male; D009412:Nerve Fibers / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D010502:Perineum / Q000294:innervation*; D013116:Spinal Cord / Q000502:physiology*; D014781:Viscera / Q000294:innervation*