title: Effect of phenobarbital on cerebral blood flow in the newborn piglet under stress.
abstract: Heart rate, cardiac output, mean arterial blood pressure (MABP), and cerebral blood flow (CBF) were measured in 12 newborn piglets (6 controls and 6 pretreated with 20 mg/kg phenobarbital), under two different stresses: pain stimulation and intravenous injection of 2.5 mg/kg phenylephrine. Phenobarbital prevented pain-induced tachycardia (p less than 0.05 versus controls) but failed to prevent hemodynamic changes induced by phenylephrine. CBF remained relatively constant throughout the study. A better correlation between cerebral vascular resistance and MABP was noted in the phenobarbital group (r = 0.58, p less than 0.01) than in the controls (r = 0.15, p = NS), suggesting that phenobarbital potentiates the vasoconstrictor effect of catecholamines.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D010146:Pain / Q000503:physiopathology; D010634:Phenobarbital / Q000494:pharmacology*; D010656:Phenylephrine; D013312:Stress, Physiological / Q000503:physiopathology*; D013552:Swine
chemical_list: D010656:Phenylephrine; D010634:Phenobarbital