Celiac ganglionectomy abolishes the chronic vasoconstrictor responses to angiotensin II (AngII) in conscious rats consuming a high salt diet

Surgical removal of the celiac sympathetic ganglion (CGx) markedly attenuates AngII‐salt hypertension. To investigate the hemodynamic mechanism of CGx in this model, rats consuming a 2.0% NaCl diet were instrumented for 24 hr/day recording of aortic pressure (AP) and ascending aortic blood flow (cardiac output; CO) using chronically implanted telemetry transmitters and Transonics flow probes respectively. At the same time rats were subjected to CGx (N=4) or SHAM surgery (N=3). AP and CO were measured for 1 week of control and 1 week after implantation of an osmotic minipump to administer AngII (150 ng/kg/min. sc). Total peripheral resistance (TPR) was calculated as AP/CO. Basal hemodynamic parameters for CGx versus SHAM rats were similar; AP ( 101 + 4 vs 102 + 2 mmHg), CO ( 61 + 5 vs 67 + 6 ml/min) and TPR (1.7 + 0.2 vs 1.6 + 0.1 arbitrary units). On Day 1 of AngII, AP was elevated in SHAM (131 + 8) but not GCx (100 + 3) rats. This was entirely due to increased TPR (2.0 + 0.1) in SHAM rats whereas CO did not change in either group. By Day 7 of AngII, AP had reached steady‐state in SHAM rats (139 + 3) as a result of a sustained increase in TPR (2.2 + 0.2) and no change in CO (63 + 6). In contrast, AP increased to 116 + in CGx rats as a result of a modest increase in CO (70 + 4) whereas TPR was not changed from control levels (1.6 + 0.2). We conclude that; (1) in rats consuming a high salt diet, AngII increases AP as a result of a sustained increase in TPR in the absence of any changes in CO and (2) the vasoconstrictor response to AngII is abolished by celiac ganglionectomy. Supported by NIH Grant HL76312.