title: The effects of calcium-blocking agents on sympathetic responses to acute haemorrhagic shock in dogs.
abstract: The effects of three calcium channel-blocking agents, verapamil, nifedipine and diltiazem, given intravenously, have been studied on the cardiovascular and sympathetic responses to acute haemorrhagic shock in anaesthetized dogs. Following acute haemorrhage, cardiac output, mean pulmonary artery pressure, mean right atrial pressure, and pulmonary capillary wedge pressure all fell, and adrenaline, noradrenaline and plasma renin activity rose. In the presence of each calcium antagonist the fall in cardiac output, mean pulmonary artery pressure, central venous pressure and pulmonary capillary wedge pressure was similar, and the rise in catecholamine levels unaffected. The rise in plasma renin activity following diltiazem 0.02 mg kg-1 or 0.1 mg kg-1 or nifedipine 0.01 mg kg-1 was similar to values in a control group, whereas in those receiving verapamil 0.15 mg kg-1 or 0.6 mg kg-1, or nifedipine 0.05 mg kg-1, the rise was greater.
authors.affiliation: Department of Anaesthesia, University of Manchester, Manchester Royal Infirmary, United Kingdom.
authors.forename: B J
authors.initials: BJ
authors.lastname: Pollard
authors.forename: I R
authors.initials: IR
authors.lastname: Fletcher
authors.forename: A R
authors.initials: AR
authors.lastname: Tait
authors.forename: P R
authors.initials: PR
authors.lastname: Knight
authors.forename: A F
authors.initials: AF
authors.lastname: Van der Spek
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004110:Diltiazem / Q000494:pharmacology; D004285:Dogs; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D009543:Nifedipine / Q000494:pharmacology; D012083:Renin / Q000097:blood; D012771:Shock, Hemorrhagic / Q000097:blood / Q000503:physiopathology*; D013564:Sympathetic Nervous System / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D014700:Verapamil; D012083:Renin; D004110:Diltiazem; D009543:Nifedipine