Development and maturation of noradrenaline-containing nerves of the rat uterine artery. Effects of acute and chronic oestrogen treatment.

The development and maturation of noradrenaline-containing nerves of the rat uterine artery was investigated, histochemically and biochemically, at seven different postnatal age-stages and following acute and chronic treatment with oestradiol. Morphological changes in the vessel were quantitatively evaluated on Toluidine Blue-stained semithin sections and low magnification electronmicrographs. In summary, the uterine artery is innervated at birth; the adult pattern of innervation is established at two weeks of age; the innervation density increases progressively between the infantile and prepubertal periods, accompanying proliferation and growth of smooth muscle cells in the tunica media; changes in the innervation are followed by an increase in the tissue concentration of noradrenaline and neither the endocrine changes characterizing puberty nor acute or chronic treatment with oestradiol have an effect on the pattern of development of the uterine artery and associated noradrenaline-containing nerves. Results are interpreted considering the differential susceptibility of urinogenital organs to sex hormones.