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Comparison of the hemodynamic responses to ketanserin and prazosin in portal hypertensive rats
Author(s) -
Cummings Susan A.,
Kaumann Alberto J.,
Groszmann Roberto J.
Publication year - 1988
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.1840080523
Subject(s) - prazosin , ketanserin , hemodynamics , medicine , cardiology , portal hypertension , antagonist , cirrhosis , receptor , 5 ht receptor , serotonin
Ketanserin, a serotonin antagonist, is effective in lowering portal pressure in a rat model of portal hypertension. As ketanserin has α 1 ‐adrenoceptor‐blocking properties in addition to its serotonin‐blocking effects, we sought to define further the mechanism of ketanserin's portal pressure‐lowering effect. We attempted to determine whether the portal pressure‐reducing effect of ketanserin was due to the unspecific effect of arterial blood pressure reduction mediated by α 1 ‐adrenoceptor blockade or to serotonin receptor‐blocking properties of ketanserin. The hemodynamic action of prazosin and α 1 ‐adrenoceptor antagonist and ketanserin were compared in portal hypertensive rats in which the arterial pressure was equally reduced by both agents. The portal pressure was significantly lower in the ketanserin‐treated group (11.3 ± 0.4 mm Hg) when compared to the saline‐treated group (13.6 ± 0.7 mm Hg). The portal pressure was not significantly lower in the prazosin‐treated group when compared to the saline‐treated group (12.3 ± 0.5 vs. 13.6 ± 0.7 mm Hg, respectively). The same relationship held true for portal venous inflow and cardiac output. For each measurement, results in the ketanserin group were significantly lower when compared to the saline‐treated group. These data in the prazosin‐treated group were similar to data in the saline‐treated group. The differences between the effect of ketanserin and prazosin were obtained despite similar blood pressure decreases. Ketanserin produced an 18% decrease and prazosin a 14% decrease in blood pressure when values were compared to their preinjection baselines. Ketanserin at the dose used lowers portal pressure primarily via serotonin blockade; α 1 ‐adrenoceptor blockade and arterial hypotension appear to play a lesser role. This finding further supports a role for serotonin in portal hypertension.