Ketanserin stabilizes blood pressure in conscious spontaneously hypertensive rats

Ithas been demonstrated thatblood pressure variability (BPV) is increased in hypertension and related to or- gan damage.It will be important to lower BPV in the treatment of hypertension.The present study was designed to investi- gate the effect of ketanserin,a 5 - HT2 Areceptor antagonist with a weakα1 - adrenoceptor blocking effect,on BPV in conscious spontaneously hypertensive rats(SHR) .It was found that ketanserin decreased blood pressure(BP) and BPV in SHR when administered intravenously(3mg/ kg,i.v.) .Ketanserin decreased BPV,butnot the BP level,when adm inistered intracere- broventricularly (5 0μg/ rat,i.c.v.) . Prazosin,allα1 - adrenoceptor antagonist,lowered BP but did not affect BPV when giv- en either i.v. (0 .5 m g/ kg) or i.c.v. (30 μg/ rat) .Ritanserin(0 .6 2 5 mg/ kg,i.v.;4 0 μg/ rat,i.c.v.) ,a5 - HT2 A receptor antagonist,decreased BPV only when administered i.c.v.,and did not modify the BP level.Ketanserin enhanced arterial baroreflex function in SHR when given either i.v. or i.c.v.. The stabilizing effect of ketanserin on BP was persistent when administered intragastrically.This adm inistration route is similar to oral adm inistration clinically.It is concluded that ke- tanserin is an antihypertensive agent with an effect of reducing BPV. This effect is m ainly mediated by central 5 - HT2 Arecep- tors and is probably attributable to the restoration of arterial baroreflex function.