Inverse association between basilar artery volume and neuron density in the stellate ganglion following bilateral common carotid artery ligation: An experimental study

OBJECTIVE: This study examined the relationship between neuron density in the stellate ganglion and the severity of basilar artery (BA) enlargement after bilateral common carotid artery ligation. METHODS: Rabbits (n = 24) were randomly divided into 3 groups: unoperated control group (n = 4), experimental group subjected to bilateral common carotid artery ligation (n [ 15), and sham-operated control group (n = 5). Histologic examination of the BAs and stellate ganglia was performed 2 months later. Permanent bilateral common carotid artery ligation was induced by ligation of common carotid arteries at prebifurcation levels as a model for steno-occlusive carotid artery disease. RESULTS: Mean BA volume and neuron density in stellate ganglia for all animals were 4200 mu m(3) +/- 240 and 8325 mu m(3) +/- 210. In sham- operated animals, the mean values were 4360 mu m(3) +/- 340 and 8250 mm(3) +/- 250. For the experimental group, mean volume and density in animals with slight dilatation of the BA (n = 6) were 4948 mu m(3) +/- 680 and 10,321 mm(3) +/- 120, whereas in animals with severe dilatation (n = 9), the values were 6728 mu m(3) +/- 440 and 6300 mm(3) +/- 730. An inverse association was observed between degree of BA enlargement and stellate ganglia neuronal density. CONCLUSIONS: High neuron density in stellate ganglia may protect against steno-occlusive carotid artery disease by preventing BA dilatation and aneurysm formation in the posterior circulatory arteries.