Pregnancy reduces noradrenaline but not neuropeptide levels in the uterine artery of the guinea-pig.
Using histochemical, immunohistochemical and biochemical techniques, noradrenaline-, neuropeptide Y-, vasoactive intestinal polypeptide-, substance P- and calcitonin gene-related peptide-containing nerve fibres were studied in the uterine artery of virgin, progesterone-treated and pregnant guinea-pigs. Morphological changes following hormone treatment or in pregnancy were also evaluated in a quantitative study on semithin sections of the uterine artery. In late pregnancy, the number of noradrenaline-containing nerve fibres, which formed the densest plexus in virgin animals, was significantly decreased, a finding supported by a significant reduction in noradrenaline levels. This reduction was not mimicked by systemic progesterone treatment. In contrast, the innervation of the uterine artery by neuropeptide Y-containing nerve fibres was increased in pregnancy, while the other peptidergic nerves and peptide levels were unchanged after progesterone treatment and in pregnancy. These changes led to a predominance of innervation by neuropeptide Y- rather than noradrenaline-containing nerve fibres in late pregnancy. No morphological changes were detected following progesterone treatment, but pregnancy led to a marked increase in the cross-sectional area of the vessel accompanied by an increase in the thickness of the media.
Department of Anatomy and Developmental Biology, University College London, United Kingdom.
M C
MC
Mione
J F
JF
Cavanagh
J
J
Lincoln
P
P
Milner
G
G
Burnstock
D000818:Animals; D001158:Arteries / Q000294:innervation; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D005260:Female; D006168:Guinea Pigs; D009412:Nerve Fibers / Q000032:analysis*; D009478:Neuropeptide Y / Q000032:analysis; D009479:Neuropeptides / Q000032:analysis*; D009638:Norepinephrine / Q000032:analysis*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology; D013373:Substance P / Q000032:analysis; D014599:Uterus / Q000098:blood supply*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D009478:Neuropeptide Y; D009479:Neuropeptides; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D011374:Progesterone; D015740:Calcitonin Gene-Related Peptide; D009638:Norepinephrine