Characterization of the vasculature supplying the genital tissues in female rats.
BACKGROUND
The internal pudendal arteries are the key resistance vessels controlling the peripheral circulatory component of sexual responses in both male and females. Previous studies in the male rat demonstrated that this vessel has markedly heightened susceptibility to vascular damage compared with other vessels in the body. Evidence suggests that the female may also be susceptible to vascular pathologies contributing to sexual dysfunction.


OBJECTIVE
The aim of this study is to characterize the anatomical, morphological, and functional properties of the pudendal artery in female rats.


METHODS
The pelvic arteries in young Sprague-Dawley female rats were dissected to generate a composite representation of the vascular gross anatomy. Morphometry was performed on perfusion-fixed pudendal arteries whereas others were mounted in a wire myograph to assess responses to vasoactive drugs. These measures were contrasted with a previous study examining male rats.


METHODS
Outcome measures used are gross anatomy, lumen diameter, wall thickness, cross-sectional area, and contractile responses in the internal pudendal artery.


RESULTS
The gross anatomy of the pudendal artery in female rats appears to parallel that found in male rats, acting as the primary feeder vessel of the clitoral, labial, and vaginal tissue. Compared with the male rat, the female pudendal artery has a smaller lumen diameter (169 ± 5.7 vs. 303 ± 13.8 µm), wall thickness (14 ± 0.7 vs. 47 ± 2.2 µm), and cross-sectional area (8 ± 0.4 vs. 52 ± 3.4 × 103 µm(2) ). These structural differences also translate into a decreased contractile capacity of the pudendal arteries from female rats vs. male rats (8.1 ± 2.7 vs. 20 ± 1.4 mN).


CONCLUSIONS
Although the gross anatomical features of the vasculature tree supplying the genital tissue in male and female rats appear to have similarities, the tissue-specific properties of the vessel itself have a very different structure-function balance. We hypothesize that this discordance likely reflects the very different sex-specific roles of this vessel in regulating blood flow during arousal.
Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada. jhannan2@jhmi.edu
Johanna L
JL
Hannan
Geoffrey L
GL
Cheung
Mark C
MC
Blaser
Judith J
JJ
Pang
Stephen C
SC
Pang
R Clinton
RC
Webb
Michael A
MA
Adams
D000818:Animals; D001158:Arteries / Q000033:anatomy & histology; D002987:Clitoris / Q000098:blood supply; D005260:Female; D005836:Genitalia, Female / Q000098:blood supply*; D006168:Guinea Pigs; D008297:Male; D010388:Pelvis / Q000098:blood supply; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D014621:Vagina / Q000098:blood supply; D014844:Vulva / Q000098:blood supply