Abstract 267: Ablation of Sympathetic Neurons Projecting to Mesenteric Blood Vessels Attenuates Nicotine-Induced Rise in Systemic Arterial Pressure

Abstract

Celiac ganglionectomy attenuates the increase in arterial pressure (AP) seen in the DOCA-salt model of hypertension; however, it is unknown which population of neurons in the celiac ganglion (CG) is responsible for this attenuation. Therefore, we ablated sympathetic post ganglionic neurons selectively innervating mesenteric blood vessels by applying a retrograde tracer, cholera toxin subunit b, conjugated to the neurotoxin saporin (CTB-SAP) on multiple, adjacent branches (~6mm) of mesenteric arteries and veins. Control animals received PBS instead of a CTB-SAP treatment. After 7-10 days rats were anesthetized, and fitted with a femoral catheter to record AP. Nicotine (200mM) was then applied to the surface of the surgically-exposed CG, which caused a significant increase in AP in control animals but not in CTB-SAP treated animals ( Table 1 ). Quantitative morphometry done on the CG revealed a significant reduction in the density of ganglionic neurons in CTB-SAP treated animals when compared to control animals ( Table 1 ). This study shows ablating CG neurons that innervate such a small portion of the mesenteric vasculature reduces the elevation of systemic AP induced by nicotine. Moreover, this study gives way for further investigations into how ablation of neurons innervating mesenteric arteries or veins can modulate AP.