**9. Experimental methods** *in vivo*

Figure 1 shows the innervations received by the ovaries and adrenals originating in the CMSG and the centers originating in the vagus nerve (Vagus centers). The CMSG and the

Fig. 1. The diagram shows the neural pathways connecting the adrenals and ovaries with the celiac-superior mesenteric ganglia (CSMG). The interconnections between the right and left CSMG, as well as the innervations to the vagus nerves are also represented.

vagus centers seem to be the place where information from other regions of the CNS converges. Both centers send and receive neural information that modulates the reactivity of the endocrine cells to hormonal signals from the ovaries and adrenals. The existence of neural communication between the right and left CMSG implies the existence of neural communication between the ovaries. The modulation exerted by the neural signals over the ovaries and the adrenals varies during the estrous cycle (ovaries) and along the day (adrenals and ovaries). Such modulation is asymmetric, and the asymmetry varies during the estrous cycle and the hour of the day.

Extirpating one ovary or one adrenal result in acute neural stimulation of the *in situ* ovary and/or adrenal, that modifies the response of endocrine cells to the hormonal signals. Sectioning one nerve also results in an acute neural stimulation of the denervated organ**,**  though such stimulation is more restricted. For the ovaries and adrenals, the partially denervated organ still has neural pathways regulating its functions and, in theory, the innervated organ received only one different neural signal.

To study the role played by the ovarian innervations in regulating progesterone, testosterone and estradiol levels in serum we have used five experimental models. The experimental models were performed on cyclic rats and our studies analyzed the influence of the day of the estrous cycle on treatment results.


16 Steroids – Basic Science

The results presented above suggest that the adrenergic activation of the CG plays a role in regulating ovarian androgen secretion, and that this role varies along the estrous cycle. Therefore, steroidogenesis appears to be controlled by a balance between the stimulatory effects of hormones secreted by the pituitary, the inhibitory effects of other hormones, and

Pituitary hormones and innervations, including sympathetic and sensory nerves, also regulate the adrenal cortex secretion of hormones. The nerves innervating the adrenal cortex include heterogeneous populations containing various different neuropeptides (Kondo, 1985). The sympathetic innervation is composed of cholinergic preganglionic fibers and catecholaminergic postganglionic fibers that are positive for tyrosine hydroxylase (TH) and NPY (Kondo, 1985; Holgert et al., 1998). Sensory innervations consist of primary afferent fibers that are positive for calcitonin gene–related peptide (CGRP) and SP (Kuramoto et al. 1987). Intrinsic innervations on the adrenal cortex arise from two types of medullar ganglion cells: Type I cells are noradrenergic and NPY-positive, whereas Type II cells produce neuronal nitric oxide synthase and VIP (Holgert et al., 1998). Preganglionic sympathetic and primary afferent

Figure 1 shows the innervations received by the ovaries and adrenals originating in the CMSG and the centers originating in the vagus nerve (Vagus centers). The CMSG and the

Adrenal Adrenal

CSMG CSMG

Vagus Centers

> RIGHT OVARY

Fig. 1. The diagram shows the neural pathways connecting the adrenals and ovaries with the celiac-superior mesenteric ganglia (CSMG). The interconnections between the right and

left CSMG, as well as the innervations to the vagus nerves are also represented.

LEFT OVARY

fibers are carried in the thoracic splanchnic nerve (Ulrich-Lai & Engeland 2000).

Vagus Centers

the modulating participation of the ovarian innervations.

**9. Experimental methods** *in vivo*

