Effects of adenosine on systemic and splanchnic hemodynamics
in conscious rats
Zhong Qiu Wang, Takuji Todani, Yasuhiro Watanabe, Kiyoshi Sasaki, Hong He,
Youichi Abe
Asia Pacific J Pharmacol 12: 45-50, 1997
Systemic and splanchnic hemodynamics were measured during the infusion of
adenosine (ADO) in conscious and normotensive Sprague-Dawley rats using
the radioactive microsphere technique . The effects of ADO were shown in
a dose-dependent fashion. Under 100 micro-g/kg/min of intravenous ADO administration,
systemic hemodynamic parameters and organ blood flow did not change significantly.
The higher dose, 500 micro-g/kg/min, rapidly reduced the mean arterial pressure
from 113+-7 to 83+-5 mmHg (25%, p<0.001) due to a reduction of total
peripheral resistance from 0.82+-0.13 to 0.60+-0.09 mmHg/min/ml (27%, p<0.001).
Cardiac output remained unchanged because of a decrease in heart rate from
411+-14 to 355+-14 beats/min (14%, p<0.001). ADO also significantly increased
blood flows to the heart, esophagus, stomach, small intestine, mesentery,
hepatic artery and portal vein. The increased magnitude ranged from 100
to 400%. The esophagus demonstrated the greatest increase in the blood flow.
No change was observed in the brain, Iungs, kidneys, colon and testis. The
blood flow decreased in the spleen. ADO receptor antagonist, 8-(p-sulfophenyl)
theophylline, significantly attenuated the ADO-induced hypotensive response
mediated by A2 receptors, and the negative chronotropic effect mediated
by A1 receptors. Therefore, ADO is possibly a potent vasodilator in the
splanchnic organs, especially in the gastrointestinal tract.
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