Autonomie Nervous System and Vegetative Control: PDF OnlyNerve fibres in the uterine artery increase in number in pregnant guinea-pigsMione, Maria Caterina; Gabella, GiorgioAuthor Information Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK NeuroReport: September 1991 - Volume 2 - Issue 9 - p 537-540 Buy Abstract PERIVASCULAR nerves of the uterine artery were studied in four-month-old pregnant and non-pregnant guinea-pigs. In pregnancy, the uterine artery hypertrophies (more than two-fold growth in diameter and length and 50% increase in wall thickness), but its density of innervation remains high, because of the growth of many new axons. The axons in a complete transverse section of the vessel increase by 40%. The nerve bundles grow by 100%. Small nerve bundles increase more than large bundles: nearly 70% of the nerve bundles contain 10 or fewer axons in pregnant guinea-pigs (37% in non-pregnant animals). The increase in axon number is accompanied by formation of new varicosities, hence presumably of new neuromuscular junctions. © Lippincott-Raven Publishers.