in case of animals pretreated with maximal threshold shock ( 36 ma , 0.2 sec ) the hypothermic action of clonidine in lower dose was blocked by all the three antagonists viz . prazosin , phenoxybenzamine and yohimbine , suggesting involvement of both alpha 1 and alpha 2-adrenoceptors , however , when clonidine was used in the higher dose , the action was significantly antagonised by prazosin and partially by yohimbine , suggesting predominant involvement of alpha 1 and partial involvement of alpha 2-adrenoceptors .
C0036974
shock
C0031441
phenoxybenzamine