suh301 antagonizes r8ohdpatinduced cardiovascular effects in the rat the 5ht1areceptor antagonist suh301 s5fluoro8hydroxy2 dipropylaminotetralin completely antagonized the hypotension and bradycardia induced by r 8oh dpat r8hydroxy2 dipropylaminotetralin in conscious rats suh301 alone induced a weak hypertension which might be due to its 5ht1areceptor antagonistic properties ruh301 induced effects similar to those of r8oh dpat ie a short initial phase of hypertension followed by a longlasting hypotension and bradycardia thus ruh301 behaves as a 5ht1areceptor agonist and suh301 as a 5ht1areceptor antagonist abolishing the effects induced by r8oh dpat the electrophoresis of histones in polyacrylamide gel and their quantitative determination 1 a new method has been devised for the separation of the histone fractions of calf thymus by electrophoresis in polyacrylamide gel at ph24 2 the fractions have been characterized by their relative mobilities with respect to a marker protein bovine plasma albumin 3 a method has been developed for the quantitative determination of the separated histone fractions by measuring the colour yields of dyehistone complexes formed in the gel