Neuropeptide Y in the female reproductive tract of the rat. Distribution of nerve fibres and motor effects.

Fluorescence immunocytochemistry revealed the presence of extensive systems of nerve fibres containing neuropeptide Y (NPY) in the rat's ovary, fallopian tube, uterine horns and cervix. The most prominent supply of NPY fibres was found in ther cervix, where they are associated with both vascular and non-vascular smooth musculature. Smooth muscle effect of NPY was studied in an in vitro model using circular cervix preparations from estrogen-treated sprayed rats. NPY onhibited in a dose-dependent way neurally evoked (tetrodotoxin-sensitive) contractions, but had no effect on resting tension. The nerve-induced contractions were blocked by atropine, the experiments thus suggest prejunctional actions of NPY in cholinergic nerves in the uterine cervix.