Structural organization of the neuronal pathways of the superior ovarian nerve in the rat

Abstract

Background: In the rat, studies have shown that ovary innervation arrives via the superior ovarian nerve (SON) and the ovarian plexus nerve, which originates from the celiac plexus (CP). In the present study, we performed a neuroanatomical technique to investigate the anatomy of the SON between the ovary and the CP.

Results: We found that the SON fibers were concentrated on the lateral border of the suprarenal ganglion and projected towards, then inserted into the suspensory ligament. Then, it ran parallel to the long axis of the ligament to reach and innervate the ovaries. At this level, the SON was composed of two coiled nerve fibers, each between 10 and 15 µm in diameter. The SON was linked to three different ganglia: the suprarenal ganglia, the celiac ganglia, and the superior mesenteric ganglion.

Conclusions: The postganglionic fibers that project to the ovary via the SON emerge from the suprarenal ganglia. The trajectories on the right and left sides to each ovary are similar. The somas of ipsilateral and contralateral SON neurons are located in the prevertebral ganglia, mostly in the celiac ganglia.

Keywords: Celiac ganglion; Ovary; Superior ovarian nerve; Suprarenal ganglion; Suspensory ligament.

Fig. 1

Photographs of abdominal tissues treated with acetylcholinesterase histochemistry show the course of the superior ovarian nerve (green arrows) and its relationship to the adrenal gland, lower-most rib, suspensory ligament (SL), kidney, and ovary in the female rat. SON, superior ovarian nerve; LSG, left suprarenal ganglion, Lag, left adrenal gland; lmsn, left major splanchnic nerve; lmisn, left minor splanchnic nerve; O, origin of SON; I, insertion of SON to the suspensory ligament; LCG, left celiac ganglion

Fig. 2

Photograph of the tissue between the left kidney and the diaphragm, treated with acetylcholinesterase histochemistry. Green arrows show the course of the superior ovarian nerve and its relationship to the left adrenal gland (Lag). SL, suspensory ligament; SON, superior ovarian nerve; LSG, left suprarenal ganglion; LCG, left celiac ganglion; lmsn, left major splanchnic nerve; lmisn, left minor splanchnic nerve; O, origin of the SON; I, insertion of the SON to the suspensory ligament

Fig. 3

Photograph of the gross anatomy of the origin of the right superior ovarian nerve. SON, superior ovarian nerve; O, origin of the SON; RSG, right suprarenal ganglion; Rag, right adrenal gland; rmsn, right major splanchnic nerve; rmisn, right minor splanchnic nerve; an, adrenal nerves

Fig. 4

Scanning electron microscope image of the superior ovarian nerve and its path to the ovary. A general organization of a transverse section of the suspensory ligament. The two nerve fibers (yellow asterisks) and blood vessels are enclosed in a thin layer of mesovarium. SL, Suspensory ligament; Obv, ovarian blood vessels; SON, superior ovarian nerve; Me, mesovarium; B detail shows that the superior ovarian nerve is formed by two nerve fibers (yellow asterisks) with collagen fibers (yellow arrow); cf, collagen fibers; C detail shows the communication between the suspensory ligament and the ovary. OV, ovary; D a postganglionic branch of the SON, in a ventro-lateral view, where it reaches the ovary. Bson, branch of the superior ovarian nerve; E, enlargement of the red boxed region in D, shows the branch of the superior ovarian nerve

Fig. 5

Anatomic schematic shows the major neural pathways that innervate the female rat ovaries. RSON, right superior ovarian nerve; LSON, Left superior ovarian nerve; ROPN, right ovarian plexus nerve; LOPN, left ovarian plexus nerve; RSG, right suprarenal ganglion; LSG, left suprarenal ganglion; RCG, right celiac ganglion; LCG, left celiac ganglion; SMG, superior mesenteric ganglion, IMG, inferior mesenteric ganglion; IRG, inter-renal ganglion; ARG, aorticorenal ganglion; sG, small ganglion; Rag, right adrenal gland; Lag, left adrenal gland; Rk, right kidney; Lk, left kidney; Rov, right ovary; Lov, left ovary, Od, oviduct; a, aorta; an, adrenal nerves; IVC, inferior vena cava; lmsn, left major splanchnic nerve; rmsn, right major splanchnic nerve; lmisn, left minor splanchnic nerve; rmisn, right minor splanchnic nerve; B, bladder; EUS, external urethral sphinter; u, urethra

Fig. 6

Representative photomicrographs of postganglionic neurons of the ovary (yellow arrowheads) labeled with True Blue stain in three different ganglia. Neural pathways are indicated in A the right suprarenal ganglion; B right celiac ganglion; and C superior mesenteric ganglion. D Schematic shows the superior ovarian nerve and its postganglionic neurons that project to the suprarenal ganglia, celiac ganglia, and superior mesenteric ganglion. SON, superior ovarian nerve; RSG, right suprarenal ganglion; RCG, right celiac ganglion; LSG, left suprarenal ganglion; LCG, left celiac ganglion; SMG, superior mesenteric ganglion