an i.c.v . injection of the alpha-adrenoceptor blocking agent phenoxybenzamine ( 10 mg ) blocked the bradycardia and hypotension produced by noradrenaline or phenylephrine , and an i.c.v . injection of a beta-adrenoceptor blocking agent , either propranolol ( 2 mg ) or n-isopropyl-p-nitrophenyl-ethanolamine ( inpea ) ( 10 mg ) , blocked the tachycardia and hypotension produced by isoprenaline.4 .
C0028351
noradrenaline
C0020649
hypotension