An investigation into the extrinsic blood supply and the microvasculature of the rat stellate ganglion

Abstract

The extrinsic supply of the rat stellate ganglion (STG) has been investigated by histological examination of the vasculature following india ink injections by a variety of routes. The main arterial supply to the STG is derived from an un-named branch of the pericardiophrenic branch of the costocervical trunk of the subclavian artery but a small contribution is made to the rostral part of the STG from microvessels running in the cervical sympathetic trunk. Similarly there are microvessels running in the nerve trunks connected to the STG and these, together with those in the cervical sympathetic trunk, can perfuse the STG when the subclavian artery is occluded. The second and third intercostal arteries do not supply the STG. Measurements of alkaline phosphate-stained microvascular endothelial cells reveal that microvessel diameters (6.5 +/- 0.54 microns) in the rat STG are comparable to those in other rat sympathetic ganglia as is the endothelial surface area available for exchange to a given volume of blood. However the density of the microvascular bed in the STG is greater (553.2 mm/mm3) than in other rat sympathetic ganglia and individual neurones in the STG are surrounded by a higher number of microvessels within a radius of 25 microns from the centre of the nucleus. These results suggest that the metabolic demands of STG neurones may be higher than in other sympathetic ganglia.