Participation of the superior ovarian nerve in the regulation of compensatory ovarian hypertrophy: the effects of its section performed on each day of the oestrous cycle

Abstract

The effects were analysed of secretion of the superior ovarian nerve on compensatory ovulation and ovarian hypertrophy, in adult rats with the left or right ovaries extirpated during the oestrous cycle and autopsied 6 or 20 days later. Rats with hemiovariectomy or hemiovariectomy plus denervation recovered their oestrous cyclicity between 2 and 3 days after surgery. Six days after hemiovariectomy 14 out of 17 rats ovulated on the expected day of oestrus. All the animals were hemiovariectomized on the day of pro-oestrus. The mean +/- S.E.M. number of ova shed was similar to the group of animals with both ovaries (7.8 +/- 1.2 vs 9.5 +/- 0.2). Compensatory ovarian hypertrophy was observed in the right ovary when left hemiovariectomy was performed on day 2 of dioestrus or pro-oestrus; similar results were observed in the left ovary when the right one was extirpated at oestrus or pro-oestrus. Section of the right superior ovarian nerve in left-hemiovariectomized rats caused a reduction in ovulation rate and number of ova released. Compensatory ovarian hypertrophy was modified in the opposite way by unilateral section of the superior ovarian nerve to the in situ ovary depending on the day of the cycle when hemiovariectomy was performed. Twenty days after treatment, ovulation rate, compensatory ovulation and ovarian hypertrophy were similar in both left- or right-hemiovariectomized rats. Compensatory ovarian hypertrophy increased in all animals with section of the superior ovarian nerve, except when hemiovariectomy was carried out at oestrus or the left ovary was extirpated on day 1 of dioestrus.(ABSTRACT TRUNCATED AT 250 WORDS)

Predominance of supraspinal innervation of the left ovary

“…Transection of the left superior ovarian nerve has been reported to decrease the number of ova shed from the left ovary and to increase the number of ova shed from the right gonad. Similar denervation on the right side was without effect (Chavez and Dominguez, 1994). In addition Morales et al (1993) observed that the asymmetry of ovarian innervation undergoes age-dependent changes.…”

“…Asymmetry of the rodent ovary includes difference in the venous drainage and functional asymmetry of the gonad in response to acute hemicastration (Barco et al, 2003;Flores et al, 2005) or to transection of the nerves supplying the gland (Chavez and Dominguez, 1994;Chavez et al, 1987Chavez et al, , 1989. Concerning asymmetry at the level of cerebral structures involved in the control of ovarian functions, observations indicate both biochemical and functional asymmetry of hypothalamic and temporolimbic structures (see for review Gerendai and Halász, 1997).…”

Effect of the relation between neural cholinergic action and nitric oxide on ovarian steroidogenesis in prepubertal rats

“…At present, there is strong evidence that SON is the way most highly involved in the ovary functioning by its participation in cell maturation and differentiation phenomena, as well as in steroidogenesis [4,7,8,13,14,16,17,19,28]. The participation of NO in these phenomena has also been demonstrated [21][22][23].…”

“…The superior ovarian nerve penetrates into the ovary through the hilium and innervates the ovarian stroma, especially the theca and secondary interstitial cells, both responsible for androgen synthesis [6][7][8][9][10][11][12]. Previous studies have revealed that coeliac ganglion stimulation [13,14] as well as section or electric stimulation of the superior ovarian nerve, produces modifications in the secretion of ovarian steroids in rats at different stages of the reproductive life [15][16][17][18][19]. The fact that the preganglionic fibers reaching the coeliac ganglion are of cholinergic nature might indicate that there exists a cholinergic modulation over the sympathetic postganglionar output acting in the ovary [9,20].…”

Acute effects of unilateral sectioning the superior ovarian nerve of rats with unilateral ovariectomy on ovarian hormones (progesterone, testosterone and estradiol) levels vary during the estrous cycle

“…According to Klein and Burden [10], the number of neural fibers received by the right ovary is higher than in the left; while, Toth et al [38] showed that the left ovary sends more neural information to the central nervous system (CNS) than the right ovary. In addition, the right and left ovaries show different ovulatory responses to surgical denervation, and these responses vary according to the day of the estrous cycle when surgery is performed [3,39]. …”