Integrative cardiovascular actions of a novel catecholamine, GP-2-128.
Systematic modification in the chemical structure of dobutamine resulted in production of a long-acting, highly potent catecholamine, GP-2-128 [(1-(3,4-dihydroxyphenyl)-2-[3-(4-carbamyl phenyl)-1-methylpropylamino] ethanol)]. The cardiovascular actions of GP-2-128 were compared with those of isoproterenol (ISO) and dobutamine (DOB) in anesthetized dogs. GP-2-128 significantly increased left ventricular pressure (LVdP/dtmax), cardiac output (CO), and heart rate (HR). It also reduced total peripheral vascular resistance (TPVR). For a given increase in contractility, changes in HR were greater after ISO than after GP-2-128 administration. DOB did not change HR significantly. Both GP-2-128 and DOB reduced TPVR, but ISO was more effective than GP-2-128 and DOB in reducing TPVR. GP-2-128 was 18,000 and 52 times more potent than DOB and ISO, respectively, in increasing LVdP/dtmax. For a given increase in contractility, the cardiovascular actions of GP-2-128 lasted significantly longer than those of DOB or ISO. A 50% mixture of the RR and RS distereoisomer forms of GP-2-128 (GP-2-114) have the same pharmacologic profile as the pure RR distereoisomer. Both GP-2-128 and GP-2-114 produced current-dependent cardiovascular actions when administered by transdermal iontophoresis. The inotropic and chronotropic effects of GP-2-128 are both largely due to stimulation of beta-adrenoceptors, as shown by receptor blockade with propranolol. GP-2-128 is a very potent, long-acting catecholamine that can be administered by other than intravenous (i.v.) route.
Abou-Mohamed
G
G
Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta 30912.
Caldwell
R W
RW
Ibrahim
T M
TM
Tuttle
R R
RR
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001549:Benzamides / Q000008:administration & dosage / Q000494:pharmacology*; D002302:Cardiac Output / Q000187:drug effects; D002317:Cardiovascular Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002395:Catecholamines / Q000008:administration & dosage / Q000494:pharmacology*; D004280:Dobutamine / Q000494:pharmacology; D004285:Dogs; D005260:Female; D006207:Half-Life; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007275:Injections, Intravenous; D007478:Iontophoresis; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D013237:Stereoisomerism; D014655:Vascular Resistance / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D001549:Benzamides; D002317:Cardiovascular Agents; D002395:Catecholamines; C087657:1-(3,4-dihydroxyphenyl)-2-(3-(4-carbamylphenyl)-1-methylpropylamino)ethanol; D004280:Dobutamine; D007545:Isoproterenol